Interview. The first meeting with a pregnant woman, as a rule, takes place in outpatient settings (antenatal clinic, perinatal centers), but it also happens in a hospital. At the first visit of the patient, the doctor should conduct a survey with a thorough history taking (general and obstetric-gynecological), assess the general condition, genital organs and, if necessary, use additional examination methods. All the information received is recorded in the outpatient card of the pregnant woman or in the history of childbirth in the hospital.
Passport data. Pay attention to the age of the pregnant woman, especially the primipara. The complicated course of pregnancy and childbirth is more often observed in "elderly" (over 30 years old) and "young" (under 18 years old) primiparas. The age of a pregnant woman 35 years and older requires prenatal diagnosis due to a higher risk of having a child with congenital and hereditary pathologies.
Complaints. First of all, they find out the reasons that prompted the woman to seek medical help. A visit to the doctor in the first trimester of pregnancy is usually associated with the cessation of menstruation and the assumption of pregnancy. Often during this period of pregnancy, patients complain of nausea, vomiting and other health disorders. With a complicated course of pregnancy (a miscarriage that has begun, an ectopic pregnancy, concomitant gynecological diseases), there may be bloody discharge from the genital tract. Complaints about violations of the functions of internal organs may be due to extragenital diseases (cardiovascular, diseases of the respiratory system, kidneys, digestive system, etc.).
The complaints of pregnant women should be treated very carefully and recorded in a medical document.
Working and living conditions. Professional, domestic and environmental hazards that can adversely affect the course of pregnancy and fetal development are carefully ascertained (living in environmentally unfavorable regions, hard physical labor, work associated with vibration, chemicals, a computer, prolonged static loads, etc.). Be sure to ask questions about smoking (including passive), alcoholism, drug addiction.
Heredity and past diseases. They find out if the family of the pregnant woman and / or her husband had multiple pregnancies, hereditary diseases (mental diseases, blood diseases, metabolic disorders), as well as congenital and hereditary developmental anomalies in the next of kin.
It is necessary to obtain information about all previously transferred diseases, starting from childhood. So, for example, rickets suffered in childhood can cause pelvic deformity, which will complicate the course of rolls. Indirect signs of transferred rickets are late teething and the beginning of walking, skeletal deformities, etc. Poliomyelitis, tuberculosis in childhood can also lead to violations of the pelvic structure. Measles, rubella, rheumatism, tonsillitis, recurrent tonsillitis and other infectious diseases often cause girls to lag behind in physical and sexual development. Diphtheria of the vulva and vagina may be accompanied by the formation of cicatricial constrictions.
Non-communicable and infectious diseases transferred in adulthood are also clarified. Diseases of the cardiovascular system, liver, lungs, kidneys and other organs can complicate the course of pregnancy and childbirth, and pregnancy and childbirth can, in turn, exacerbate chronic diseases or cause relapses.
If there was a history of surgical interventions, then it is better to obtain medical documents about them with recommendations from specialists on the tactics of conducting a real pregnancy and childbirth. Of great importance are information about past injuries (skull, pelvis, spine, etc.).
menstrual function. Find out at what age the first menstruation appeared (menarche), after what period of time regular menstruation was established; the duration of the menstrual cycle, the duration of menstruation, the amount of blood lost, soreness; whether the nature of menstruation has changed after the onset of sexual activity, childbirth, abortion; first day of last menstruation.
sexual function. They collect information about the onset of sexual activity, find out what marriage is in a row, whether there are pains and bloody discharge during sexual intercourse, what methods of contraception were used before pregnancy, and the interval from the beginning of regular sexual activity to the onset of pregnancy. The absence of pregnancy within 1 year of regular sexual activity without the use of contraceptives may indicate infertility and indicate certain disorders of the reproductive system.
Information about the husband (partner) of the pregnant woman is also required: his state of health, age, profession, smoking, alcoholism, drug addiction.
Gynecological history. It is necessary to obtain information about past gynecological diseases that may affect the course of pregnancy, childbirth and the postpartum period (uterine fibroids, tumors and tumor-like formations of the ovaries, diseases of the cervix, etc.). Particular attention should be paid to previous surgical interventions on the genitals, primarily on the uterus, leading to the formation of a scar (myomectomy). An extract from a medical institution with a detailed description of the operation performed is required. For example, in case of myomectomy, it is necessary to obtain information about the access of surgical intervention (laparotomic or laparoscopic), with or without opening the uterine cavity, etc.
Find out the pregnant woman's complaints about pathological discharge from the genital tract (abundant, purulent, mucous, bloody, etc.), which may indicate a gynecological disease.
It is important to get information about past sexually transmitted diseases (HIV infection, syphilis, gonorrhea, chlamydia, etc.).
Obstetric history. First of all, it is necessary to clarify what the real pregnancy is (first, repeated) and what kind of childbirth is coming.
In foreign literature, the following concepts are distinguished.
- Nulligravida - a woman who is not currently pregnant and has no history of pregnancy.
- Gravida - a woman who is currently pregnant or has had pregnancies in the past, regardless of their outcome. During the first pregnancy, a woman is considered primigravida (primigravida), and in subsequent pregnancies - re-pregnant (multigravida).
- Nullipara - a woman who has never had a pregnancy that has reached the term of a viable fetus; she may or may not have previously had pregnancies that ended in abortion at an earlier date.
- Primipara - a woman who carried one pregnancy (single or multiple) to the term of the birth of a viable fetus.
- Multipara - a woman with a history of several pregnancies, full-term to the term of a viable fetus (22 weeks of pregnancy, fetal weight 500 g, height 32-34 cm).
Note the number of artificial or spontaneous abortions (miscarriages). If there were abortions, then at what stage of pregnancy, were they accompanied by complications (endometritis, inflammatory diseases uterus, uterine perforation, etc.). If possible, specify the cause of spontaneous abortion. Abortions preceding pregnancy can lead to miscarriage, a pathological course of childbirth.
Multiparous women receive detailed information about how previous pregnancies and childbirth proceeded. If there were complications of pregnancy (preeclampsia, miscarriage, etc.), then detailed information is needed about this, since they are important in predicting the course and outcome of this pregnancy and the upcoming birth. Find out whether the birth was timely, premature or late, spontaneous or operative (caesarean section, obstetric forceps, vacuum extraction of the fetus).
When delivering by cesarean section, it is necessary to clarify, if possible, the indications for it, whether it was performed on a planned or emergency basis, how the postoperative period proceeded, on what day after the operation the patient was discharged.
When taking an obstetric history, special attention should be paid to the condition of the child at birth (weight, length, Apgar score, whether the child was discharged from the maternity hospital or transferred to the 2nd stage of nursing and in connection with this), as well as the psychophysical development of the child at present day. In case of an unfavorable outcome, it is necessary to find out at what stage the death of the fetus / newborn occurred: during pregnancy (antenatal death), during childbirth (intranatal death), in the early neonatal period (postnatal death). It should also clarify the possible cause of death (asphyxia, birth trauma, hemolytic disease, malformations, etc.).
Detailed information about the course and outcomes of previous pregnancies and childbirth allows us to identify high-risk patients who need special attention and more careful monitoring.
Objective examination. After getting acquainted with the anamnesis, the patients proceed to an objective study, which begins with an examination.
At examination pay attention to the growth of the pregnant woman, physique, fatness, the condition of the skin, visible mucous membranes, mammary glands, the size and shape of the abdomen.
The skin during pregnancy may have certain features: pigmentation of the face, nipple area, white line of the abdomen. In the second half of pregnancy, so-called pregnancy bands often appear. Combs, ulcers on the skin require a special examination. Paleness of the skin and visible mucous membranes, cyanosis of the lips, yellowness of the skin and sclera, swelling are signs of a number of serious diseases.
To objective signs former pregnancy and childbirth include a decrease in the tone of the muscles of the anterior abdominal wall, the presence striae gravidarum.
Pay attention to the physique, possible deformations of the skeleton, as they can affect the structure of the pelvis.
Violations of the hormonal regulation of the reproductive system can lead to underdevelopment of the mammary glands, insufficient expression of hair growth in the axillary region and on the pubis, or, conversely, excessive hair growth on the face, lower extremities, and along the midline of the abdomen. In women, the features of masculinization are possible - broad shoulders, male structure of the pelvis.
The severity of subcutaneous adipose tissue should be assessed. Both alimentary and endocrine obesity of the II-III degree adversely affects the course of pregnancy and childbirth.
Measure the height and determine the body weight of the pregnant woman. When determining body weight, one should take into account not its absolute values, but the body mass index, which is calculated taking into account the height of the patient [body weight in kilograms / (height in meters) 2], which is normally 18-25 kg / m2. With low stature (150 cm and below), narrowing of the pelvis of varying degrees is often observed, women of high stature often have a male-type pelvis.
Examination of the abdomen in the third trimester of pregnancy allows you to find out deviations from its normal course. In normal pregnancy and the correct position of the fetus, the abdomen has an ovoid (ovoid) shape; with polyhydramnios, the abdomen is spherical, its size exceeds the norm for the expected gestational age; in the transverse position of the fetus, the abdomen takes the form of a transverse oval. With overstretching or divergence of the muscles of the anterior abdominal wall (more often in multiparous), the abdomen may be sagging. The shape of the abdomen also changes with a narrow pelvis.
Examination of internal organs(cardiovascular system, lungs, digestive organs, kidneys), as well as the nervous system, is carried out according to the system generally accepted in therapy.
Obstetric examination includes determining the size of the uterus, examining the pelvis, assessing the position of the fetus in the uterus based on special obstetric techniques. Methods of obstetric examination depend on the gestational age.
In the first trimester of pregnancy, the size of the uterus is determined by a two-handed vaginal-abdominal examination, which begins with an examination of the external genitalia. The study is carried out in sterile rubber gloves on a gynecological chair. The woman lies on her back, her legs are bent at the hip and knee joints and divorced; when examining on a bed, a roller is placed under the sacrum.
The external genital organs are treated with an antiseptic solution. The large and small labia are parted with I and II fingers of the left hand and examine the external genital organs (vulva), the mucous membrane of the entrance to the vagina, the external opening of the urethra, the excretory ducts of the large glands of the vestibule and the perineum.
In order to examine the walls of the vagina and cervix, examination with mirrors. This determines the cyanosis due to pregnancy, and various pathological changes in the disease of the vagina and cervix. Vaginal mirrors (Fig. 6.1) are folding, spoon-shaped, metal or plastic. The folded speculum is inserted to the fornix of the vagina in a closed form, then the folds are opened, and the cervix becomes available for inspection. The walls of the vagina are examined with the gradual removal of the mirror from the vagina.
Rice. 6.1. Vaginal mirrors (A - folding, B - spoon-shaped, C - lift)With a vaginal (finger) examination fingers of the left hand spread large and small labia; the fingers of the right hand (II and III) are inserted into the vagina, the I finger is retracted upward, IV and V are pressed against the palm and rest against the perineum. This determines the condition of the muscles of the pelvic floor, the walls of the vagina (folding, extensibility, loosening), the vaults of the vagina, the cervix (length, shape, consistency) and the external pharynx of the cervix (closed, open, round or slit-like).
An important criterion for former births is the shape of the external os of the cervix, which in those who have given birth has the shape of a longitudinal slit, and in those who have not given birth it is round or dotted (Fig. 6.2). Women who have given birth may have cicatricial changes after ruptures of the cervix, vagina and perineum.
After palpation of the cervix, proceed to two-handed vaginal-abdominal examination(Fig. 6.3). With the fingers of the left hand, gently press on the abdominal wall towards the pelvic cavity towards the fingers of the right hand, located in the anterior fornix of the vagina. Bringing together the fingers of both examining hands, palpate the body of the uterus and determine its position, shape, size and consistency. After that, they begin to study the fallopian tubes and ovaries, gradually moving the fingers of both hands from the corner of the uterus to the side walls of the pelvis. To determine the capacity and shape of the pelvis, the inner surface of the bones of the pelvis, sacral cavity, side walls of the pelvis and symphysis are examined.
When examining a pregnant woman in the II-III trimesters, it is necessary to measure the circumference of the abdomen at the level of the navel (Fig. 6.4) and the height of the fundus of the uterus (Fig. 6.5) with a centimeter tape when the woman is lying on her back. The height of the fundus of the uterus above the pubic joint can also be determined by a tazomer. These measurements are carried out at each visit to the pregnant woman and compare the data obtained with gestational standards.
Normally, by the end of pregnancy, the abdominal circumference does not exceed 100 cm, and the height of the uterine fundus is 35-36 cm. An abdominal circumference of more than 100 cm is usually observed with polyhydramnios, multiple pregnancy, large fetus, transverse position of the fetus and obesity.
Determining the size of the pelvis seems extremely important, since their decrease or increase can lead to a significant disruption in the course of labor. The dimensions of the small pelvis are of the greatest importance during childbirth, which are judged by measuring certain sizes of the large pelvis with the help of a special tool - a tazomer (Fig. 6.6).
The tazomer has the form of a compass, equipped with a scale on which centimeter and half-centimeter divisions are applied. At the ends of the branches of the tazomer there are buttons that are applied to the protruding points of the large pelvis, somewhat squeezing the subcutaneous fatty tissue. To measure the transverse size of the outlet of the pelvis, a tazomer with crossed branches was designed.
The pelvis is measured with the woman lying on her back with her stomach bare and her legs folded. The doctor becomes to the right of the pregnant woman facing her. The branches of the tazomer are picked up in such a way that the I and II fingers hold the buttons. The scale with divisions is directed upwards. Forefingers feel for the points, the distance between which is to be measured, pressing the buttons of the parted branches of the tazomer to them. On the scale mark the value of the corresponding size.
Determine the transverse dimensions of the pelvis - distantia spinarum, distantia cristarun, distantia trochanterica and straight size - conjugata externa.
Distantia spinarum - distance between the anterior superior iliac spines. The buttons of the tazomer are pressed against the outer edges of the anterior superior spines. This size is usually 25-26 cm (Fig. 6.7, a).
Distantia cristarum - the distance between the most distant points of the iliac crests. After measurement distantia spinarum the buttons of the tazomer are moved from the spines but to the outer edge of the iliac crests until the greatest distance is determined. On average, this size is 28-29 cm (Fig. 6.7, b).
Distantia trochanterica - distance between the greater trochanters of the femur. The most protruding points of the large skewers are determined and the buttons of the tazomer are pressed against them. This size is 31-32 cm (Fig. 6.7, c).
The ratio of transverse dimensions is also important. Normally, the difference between them is 3 cm; a difference of less than 3 cm indicates a deviation from the norm in the structure of the pelvis.
Conjugata externa- external conjugate, allowing to indirectly judge the direct size of the small pelvis. To measure it, a woman should lie on her left side, bending her left leg at the hip and knee joints, and keep her right leg extended. The button of one branch of the tazomer is placed in the middle of the upper outer edge of the symphysis, the other end is pressed against the supracacral fossa, which is located under the spinous process of the V lumbar vertebra, corresponding to the upper corner of the sacral rhombus. You can determine this point by sliding your fingers down the spinous processes of the lumbar vertebrae. The fossa is easily identified under the projection of the spinous process of the last lumbar vertebra. The outer conjugate is normally 20-21 cm (Fig. 6.7, d).
The external conjugate is important - by its size one can judge the size of the true conjugate (the direct size of the entrance to the small pelvis). To determine the true conjugate, subtract from the length of the outer conjugate9 cm. For example, if the outer conjugate is20 cm, then the true conjugate is11 cm; if the outer conjugate has a length18 cm, then the true value is equal to9 cmetc.
The difference between the external and true conjugate depends on the thickness of the sacrum, symphysis and soft tissues. The thickness of the bones and soft tissues in women is different, so the difference between the size of the outer and true conjugates does not always correspond exactly to 9 cm. The true conjugate can be more accurately determined by the diagonal conjugate.
Diagonal conjugate ( conjuigata diagonalis) is the distance between the lower edge of the symphysis and the most protruding part of the promontory of the sacrum. This distance can be measured only during vaginal examination, if the middle finger reaches the sacral promontory (Fig. 6.8). If this point cannot be reached, then the distance exceeds 12.5-13 cm and, therefore, the direct size of the entrance to the pelvis is within the normal range: equal to or greater than 11 cm. If the sacral cape is reached, then the point of contact with the lower edge is fixed on the arm symphysis, and then measure this distance in centimeters.
To determine the true conjugate, 1.5–2 cm is subtracted from the size of the diagonal conjugate.
If during the examination of a woman there is a suspicion of a narrowing of the exit of the pelvis, then the dimensions of the exit plane are determined.
The dimensions of the outlet of the pelvis are determined as follows. The woman lies on her back, her legs are bent at the hip and knee joints, divorced and pulled up to the stomach.
Straight size the exit of the pelvis is measured with a conventional tazometer. One button of the tazomer is pressed to the middle of the lower edge of the symphysis, the other to the top of the coccyx (Fig. 6.9, a). The resulting size (11 cm) is larger than the true one. To determine the direct size of the pelvic outlet, subtract 1.5 cm (tissue thickness) from this value. In a normal pelvis, the direct size of the plane is 9.5 cm.
Transverse dimension exit - the distance between the inner surfaces of the ischial bones - is quite difficult to measure. This size is measured with a centimeter or a pelvis with crossed branches in the position of a woman on her back with her legs brought to her stomach. There is subcutaneous fatty tissue in this area, so 1-1.5 cm is added to the resulting size. Normally, the transverse size of the pelvic outlet is 11 cm (Fig. 6.9, b).
In the same position, women measure the characteristics of the small pelvis pubic angle, applying I fingers to the pubic arches. With normal size and normal shape of the pelvis, the angle is 90 °.
When deforming the pelvic bones, the oblique dimensions of the pelvis are measured. These include:
The distance from the anterior superior iliac spine of one side to the posterior superior spine of the other side and vice versa;
Distance from the upper edge of the symphysis to the right and left posterior superior spines;
Distance from the supra-sacral fossa to the right or left anterior superior spines.
The oblique dimensions of one side are compared with the corresponding oblique dimensions of the other. With a normal structure of the pelvis, the size of the paired oblique dimensions is the same. A difference greater than 1 cm indicates an asymmetric pelvis.
If necessary, to obtain additional data on the size of the pelvis, its compliance with the size of the fetal head, deformities of the bones and their joints, an X-ray examination of the pelvis is performed - X-ray pelviometry (according to indications).
For the purpose of an objective assessment of the thickness of the pelvic bones, the circumference of the pregnant woman's wrist joint is measured with a centimeter tape (Soloviev's index; Fig. 6.10). The average value of this circumference is 14 cm. If the index is larger, it can be assumed that the pelvic bones are massive and the dimensions of its cavity are smaller than would be expected from the results of measuring the large pelvis.
Indirect signs of a correct physique and normal sizes pelvis are the shape and size of the sacral rhombus (Michaelis rhombus). The upper border of the Michaelis rhombus is the last lumbar vertebra, the lower one is
sacrococcygeal articulation, and the lateral angles correspond to the posterior superior iliac spines (a sacral rhombus of the classical form can be seen at the statue of Venus de Milo). Normally, pits are visible in all four corners (Fig. 6.11). The dimensions of the rhombus are measured with a centimeter tape, normally the longitudinal size is 11 cm, the transverse size is 10 cm.
External obstetric examination. obstetric terminology. The abdomen is palpated in the position of the pregnant woman on her back with her legs bent at the hip and knee joints. The doctor is to the right of the pregnant woman facing her.
On palpation of the abdomen, the condition of the abdominal wall, rectus abdominis muscles is determined (if there are any discrepancies, hernial protrusions, etc.). The tone of the muscles of the abdominal wall is of great importance for the course of childbirth.
Then they proceed to determine the size of the uterus, its functional state (tone, tension during the study, etc.) and the position of the fetus in the uterine cavity.
Of great importance is the determination of the position of the fetus in the uterus. In the III trimester of pregnancy, especially before childbirth and during childbirth, determine the articulation, position, position, appearance, presentation of the fetus (Fig. 6.12).
During palpation of the abdomen, the so-called external methods of obstetric research (Leopold's methods) are used. Leopold (1891) proposed a system of palpation of the abdomen and typical palpation techniques that have received universal recognition.
First external obstetric examination(Fig. 6.13, a). The goal is to determine the height of the uterine fundus and the part of the fetus located in its fundus.
The palms of both hands are placed on the uterus in such a way that they tightly cover its bottom, and the fingers are turned with the nail phalanxes to each other. Most often, at the end of pregnancy, the buttocks are determined in the bottom of the uterus. Usually it is not difficult to distinguish them from the head, since the pelvic end is less dense and does not have a clear sphericity.
The first external obstetric examination makes it possible to judge the gestational age (by the height of the fundus of the uterus), the position of the fetus (if one of its large parts is determined in the fundus of the uterus, then there is a longitudinal position) and presentation (if the buttocks are determined in the fundus of the uterus , then the presenting part is the head).
Second external obstetric examination(Fig. 6.13, b). The goal is to determine the position of the fetus, which is judged by the location of the back and small parts of the fetus (handles, legs).
Hands are shifted from the bottom of the uterus to its right and left sides to the level of the navel and below. Gently pressing the palms and fingers of both hands on the side walls of the uterus, determine which way the back and small parts of the fetus are facing. The backrest is recognized as a wide and curved surface. Small parts of the fetus are determined on the opposite side in the form of small mobile tubercles. In multiparous women, due to the flabbiness of the abdominal wall and the muscles of the uterus, small parts of the fetus are more easily palpable.
By the direction in which the back of the fetus is facing, its position is recognized: the back to the left is the first position, the back to the right is the second position.
In the process of conducting the second appointment of an external obstetric examination, it is possible to determine the excitability of the uterus. Excitability is increased if the uterus tenses in response to palpation. You can determine the increased amount of amniotic fluid by the symptom of fluctuation -
one hand takes the push of the opposite.
The third reception of external obstetric examination(Fig. 6.13, c). Target -
determine the presenting part and its relation to the small pelvis.
One, usually right, hand covers the presenting part, after which they carefully move this hand to the right and left. This technique allows you to determine the presenting part (head or buttocks), the ratio of the presenting part to the entrance to the small pelvis (if it is mobile, then it is located above the entrance to the pelvis, if it is motionless, then it stands at the entrance to the pelvis or in deeper parts of the small pelvis).
The fourth reception of external obstetric examination(Fig. 6.13, d). Target -
determine the presenting part (head or buttocks), the location of the presenting part (above the entrance to the small pelvis, in the entrance or deeper, where exactly), in what position is the presenting head (bent or unbent).
The doctor becomes facing the legs of a pregnant or woman in labor and puts his palms on both sides of the lower part of the uterus. With the fingers of both hands facing the entrance to the pelvis, carefully and slowly penetrate between the presenting part and the lateral sections of the entrance to the pelvis and palpate the available areas of the presenting part.
If the presenting part is movable above the entrance to the pelvis, the fingers of both hands can be brought almost entirely under it, especially in multiparous women. It also determines the presence or absence of symptom of balloting, characteristic of the head. To do this, the palms of both hands are pressed tightly against the lateral sections of the fetal head, then a push is made with the right hand in the region of the right half of the head. In this case, the head is repelled to the left and transmits a push to the left hand .
In cephalic presentation, one should strive to get an idea of the size of the head and the density of the bones of the skull, the location of the occiput, forehead and chin, as well as their relationship to each other.
Using the fourth technique, it is possible to determine the presence or absence of an angle between the back of the head and the back of the fetus (the higher the chin with the head fixed at the entrance, the more pronounced the flexion and the more smoothed the angle between the back of the head and the back, and vice versa, the lower the chin is, the more it is extended head), the position and appearance of the fetus according to where the back of the head, forehead, and chin are facing. For example, the back of the head is turned to the left and anteriorly - the first position, front view; the chin is turned to the left and forward - the second position, rear view, etc.
With cephalic presentation, it is also necessary to determine the depth of the head. At the fourth external obstetric examination, the fingers of both hands make a sliding movement along the head in the direction towards themselves. With a high standing of the fetal head, when it is movable above the entrance, you can bring the fingers of both hands under it and even move it away from the entrance (Fig. 6.14, a). If at the same time the fingers diverge, the head is located at the entrance to the small pelvis with a small segment (Fig. 6.14, b). If the hands sliding along the head converge, then the head is either located in a large segment at the entrance, or passed through the entrance and descended into deeper sections (planes) of the pelvis (Fig. 6.14, c). If the fetal head is located in the pelvic cavity so low that it completely fulfills it, then it is usually not possible to probe the head with external methods.
Auscultation. The heartbeat of the fetus in a pregnant woman and a woman in labor is usually listened to with an obstetric stethoscope. His wide funnel is applied to the woman's stomach.
Auscultation reveals fetal heart sounds. In addition, you can catch other sounds emanating from the mother's body: the beating of the abdominal aorta, coinciding with the woman's pulse; "blowing" uterine noises that occur in large blood vessels passing along the side walls of the uterus (coincide with the woman's pulse); irregular bowel sounds. Fetal heart sounds give an idea of the condition of the fetus.
Fetal heart sounds are heard from the beginning of the second half of pregnancy and become clearer every month. They are heard from the side of the back of the fetus, and only with facial presentation, the heartbeat of the fetus is more clearly heard from the side of its chest. This is due to the fact that with facial presentation, the head is maximally extended and the breast is adjacent to the wall of the uterus closer than the back.
With occipital presentation, the heartbeat is well heard below the navel on the left in the first position, on the right - in the second (Fig. 6.16). In breech presentation, the heartbeat is heard at or above the navel.
In transverse positions, the heartbeat is heard at the level of the navel closer to the fetal head.
In multiple pregnancies, the fetal heartbeat is usually clearly heard in different parts of the uterus.
During childbirth, when the fetal head is lowered into the pelvic cavity and its birth, the heartbeat is better heard closer to the symphysis, almost along the midline of the abdomen.
ADDITIONAL EXAMINATION METHODS IN OBSTETRICS AND PERINATOLOGY
Assessment of fetal cardiac activity. Cardiac activity is the most accurate and objective indicator of the state of the fetus in the ante- and intranatal periods. For its assessment, auscultation with an obstetric stethoscope, electrocardiography (direct and indirect), phonocardiography and cardiotocography are used.
Indirect electrocardiography carried out by applying electrodes to the anterior abdominal wall of the pregnant woman (the neutral electrode is located on the thigh). Normally, the ventricular complex is clearly visible on the electrocardiogram (ECG). QRS, sometimes prong R. Maternal complexes are easy to differentiate with simultaneous recording of the mother's ECG. The fetal ECG can be recorded from the 11-12th week of pregnancy, but it can be recorded in 100% of cases only by the end of the third trimester. As a rule, indirect electrocardiography is used after 32 weeks of pregnancy.
Direct electrocardiography is performed by applying electrodes to the fetal head during childbirth with the opening of the cervix by 3 cm or more. An atrial wave is noted on a direct ECG. R, ventricular complex QRS and prong T.
When analyzing the antenatal ECG, the heart rate, rhythm, size and duration of the ventricular complex, as well as its shape are determined. Normally, the rhythm of the heartbeat is correct, the heart rate ranges from 120 to 160 minutes, the tooth R pointed, the duration of the ventricular complex is 0.03-0.07 s, the voltage is 9-65 μV. With increasing gestational age, the voltage gradually increases.
Phonocardiogram(FCG) of the fetus is recorded when a microphone is applied at the point of best listening to its heart sounds with a stethoscope. It is usually represented by two groups of oscillations that reflect I and II heart sounds. Sometimes III and IV tones are registered. The duration and amplitude of heart sounds fluctuate markedly in the third trimester of pregnancy, on average, the duration of the first tone is 0.09 s (0.06-0.13 s), the second tone is 0.07 s (0.05-0.09 s) .
With simultaneous registration of ECG and FCG of the fetus, it is possible to calculate the duration of the phases of the cardiac cycle: phases of asynchronous contraction (AC), mechanical systole (Si), total systole (So), diastole (D). The phase of asynchronous contraction is detected between the beginning of the tooth Q and I tone, its duration is 0.02-0.05 s. Mechanical systole is the distance between the beginning of I and II tone and lasts from 0.15 to 0.22 s.
The general systole includes a mechanical systole and an asynchronous contraction phase. Its duration is 0.17-0.26 s. Diastole is calculated as the distance between the beginning of II and I tone, its duration is 0.15-0.25 s. The ratio of the duration of total systole to the duration of diastole at the end of an uncomplicated pregnancy averages 1.23.
Despite the high information content, the methods of fetal electrocardiography and phonocardiography are laborious, and the analysis of the data obtained takes a long time, which limits their use for a quick assessment of the fetal condition. In this regard, at present, cardiotocography is widely used in obstetric practice (from the 28-30th week of pregnancy).
Cardiotocography. There are indirect (external) and direct (internal) cardiotocography. During pregnancy, only indirect cardiotocography is used; at present, it is also used in childbirth, since the use of external sensors has practically no contraindications and does not cause any complications (Fig. 6.17).
An external ultrasonic sensor is placed on the anterior abdominal wall of the mother in the place of the best audibility of the fetal heart sounds, an external strain gauge is applied in the area of the uterine fundus. When using the internal registration method during childbirth, a special spiral electrode is fixed on the skin of the fetal head.
The study of the cardiotocogram (CTG) begins with the determination of the basal rhythm (Fig. 6.18). The basal rhythm is understood as the average value between the instantaneous values of the fetal heartbeat, which remains unchanged for 10 minutes or more; at the same time, acceleration and deceleration are not taken into account.
When characterizing the basal rhythm, it is necessary to take into account its variability, i.e. the frequency and amplitude of instantaneous changes in the fetal heart rate (instantaneous oscillations). The frequency and amplitude of instantaneous oscillations are determined for each subsequent 10 minutes. The amplitude of the oscillations is determined by the magnitude of the deviation from the basal rhythm, the frequency is determined by the number of oscillations in 1 min.
In clinical practice, the following classification of types of basal rate variability is most widely used:
Silent (monotone) rhythm with low amplitude (0.5 per minute);
Slightly undulating (5-10 per minute);
Undulating (10-15 per minute);
Saltatory (25-30 per minute).
Variability in the amplitude of instantaneous oscillations can be combined with a change in their frequency.
The recording is carried out in the position of the woman on the left side for 40-60 minutes.
To unify and simplify the interpretation of antenatal CTG data, a scoring system has been proposed (Table 6.1).
Table 6.1. Prenatal Fetal Cardiac Assessment Scale
A score of 8-10 points indicates normal condition fetus, 5-7 points - indicates the initial signs of a violation of his life, 4 points or less - to serious changes in the condition of the fetus.
In addition to the analysis of fetal cardiac activity at rest, using cardiotocography, it is possible to assess the reactivity of the fetus during pregnancy by changing its cardiac activity in response to spontaneous movements. This is a non-stress test (NST) or a stress test for the administration of oxytocin to the mother, a short breath-hold on inhalation or exhalation, thermal stimulation of the skin of the abdomen, physical activity, stimulation of the nipples or acoustic stimulation.
It is advisable to start the study of fetal cardiac activity with the use of NBT.
Nestreccotest. The essence of the test is to study the reaction of the fetal cardiovascular system to its movements. NST is called reactive if two increases in the fetal heart rate or more are observed within 20 minutes, at least 15 per minute and lasting at least 15 s, associated with fetal movements (Fig. 6.19). NBT is considered unresponsive for less than two fetal heart rate increases of less than 15 beats per minute for less than 15 seconds for 40 minutes.
Oxytocin test(contractile stress test). The test is based on the response of the fetal cardiovascular system to induced uterine contractions. A woman is injected intravenously with a solution of oxytocin containing 0.01 IU in 1 ml of isotonic sodium chloride solution or 5% glucose solution. The test can be evaluated if at least three uterine contractions are observed within 10 minutes at an infusion rate of 1 ml / min. With sufficient compensatory capabilities of the fetoplacental system, in response to uterine contraction, a mildly pronounced short-term acceleration or early short-term deceleration is observed.
Contraindications to the oxytocin test: pathology of placenta attachment and its partial premature detachment, threatened miscarriage, uterine scar.
When determining the state of the fetus in childbirth, CTG evaluates the basal rhythm of the heart rate, the variability of the curve, as well as the nature of slow accelerations (accelerations) and decelerations (decelerations) of the heart rate, comparing them with data reflecting the contractile activity of the uterus.
Depending on the time of occurrence relative to uterine contractions, four types of decelerations are distinguished: dip 0, dip I, dip II, dip III. The most important parameters of decelerations are the duration and amplitude of the time from the onset of contraction to the onset of slowdown. In the study of the time relationships of CTG and histograms, early (the beginning of the decrease in heart rate coincides with the onset of the contraction), late (30-60 s after the onset of uterine contraction), and decreases outside the contraction (after 60 s or more) are distinguished.
Dip 0 usually occurs in response to uterine contractions, less often sporadically, lasts 20-30 seconds and has an amplitude of 30 per minute or more. In the second stage of labor, it has no diagnostic value.
Dip 1 (early deceleration) is a reflex reaction of the fetal cardiovascular system to compression of the head or umbilical cord during contraction. Early deceleration begins simultaneously with a contraction or with a delay of up to 30 seconds and has a gradual beginning and end (Fig. 6.20). The duration and amplitude of decelerations correspond to the duration and intensity of the contraction. Dip 1 is equally common in physiological and complicated births.
Dip II (late deceleration) is a sign of impaired uteroplacental circulation and progressive fetal hypoxia. Late deceleration occurs in connection with the contraction, but is significantly delayed - up to 30-60 s from its onset. The total duration of decelerations is usually more than 1 min. There are three degrees of severity of decelerations: mild (decreasing amplitude up to 15 per minute), medium (16-45 per minute) and severe (more than 45 per minute). In addition to the amplitude and total duration of late deceleration, the severity of the pathological process reflects the time of recovery of the basal rhythm. V-, U- and W-shaped decelerations are distinguished by shape.
Dip III is called variable deceleration. Its appearance is usually associated with the pathology of the umbilical cord and is explained by stimulation of the vagus nerve and secondary hypoxia. The amplitude of variable decelerations ranges from 30 to 90 per minute, and the total duration is 30-80 seconds or more. Decelerations are very diverse in form, which greatly complicates their classification. The severity of variable decelerations depends on the amplitude: mild - up to 60 per minute, moderate - from 61 to 80 per minute and severe - more than 80 per minute.
In practice, the most convenient assessment of the state of the fetus is the time of delivery on the scale proposed by G.M. Savelieva (1981) (Table 6.2).
Table 6.2. The scale for assessing the cardiac activity of the fetus during childbirth (Saveleva G.M., 1981)
Period childbirth | Options cardiac activities | Norm | Initial signs hypoxia | Expressed signs hypoxia |
Basal heart rate | Bradycardia (up to 100) Tachycardia (no more than 180) | Bradycardia (less than 100) |
||
Instant fluctuations in heart rate (ICHR) | Periodic monotonicity (0-2) | Persistent monotony (0-2) |
||
Reaction to the fight | Missing; increase in the amplitude of the MCHR; early slowdowns | Short-term late slowdowns | Long late slowdowns |
|
Bradycardia | Bradycardia (less than 100 with a progressive drop in frequency); tachycardia (more than 180) |
|||
Periodic monotonicity | monotone; pronounced arrhythmia |
|||
Reaction to push | Early slowdowns (up to 80 per minute); W-shaped variable slowdowns (up to 75-85 per minute); short-term increases (up to 180 per minute) | Late slowdowns (up to 60 per minute); W-shaped variable slowdowns (up to 60 per minute) | Long late reductions (up to 50 per minute); long-term W-shaped variable slowdowns (up to 40 per minute) |
When using cardiotocography during childbirth, a constant assessment of the fetal cardiac activity throughout their entire length is necessary.
Ultrasound scanning (sonography). Ultrasound examination (ultrasound) is currently the only highly informative, harmless and non-invasive method that allows you to objectively monitor the development of the embryo from the earliest stages and conduct dynamic monitoring of the fetus. The method does not require special preparation of the pregnant woman. In obstetric practice, transabdominal and transvaginal scanning is used.
Establishing pregnancy and assessing its development in the early stages are the most important tasks of ultrasound diagnostics in obstetrics (Fig. 6.21).
Diagnosis of uterine pregnancy with ultrasound is possible from the earliest possible date. From the 3rd week, a fetal egg begins to be visualized in the uterine cavity in the form of an echo-negative formation of a rounded or ovoid shape with a diameter of 5-6 mm. At 4-5 weeks, it is possible to identify an embryo - an echopositive strip 6-7 mm in size. The head of the embryo is identified from 8-9 weeks in the form of a separate anatomical formation of a rounded shape with an average diameter of 10-11 mm.
The most accurate indicator of the gestational age in the first trimester is the coccyx-parietal size (KTR) (Fig. 6.22). When the embryo is not yet visible or is difficult to detect, it is advisable to use the average internal diameter of the fetal egg to determine the gestational age.
The assessment of the vital activity of the embryo in the early stages of gestation is based on the registration of its cardiac activity and motor activity. With ultrasound, it is possible to record the cardiac activity of the embryo from the 4-5th week. The heart rate gradually increases from 150-160 per minute in 5-6 weeks. to 175-185 per minute at 7-8 weeks, followed by a decrease to 150-160 per minute by 12 weeks. Motor activity is detected from 7-8 weeks.
When studying the development of the fetus in the II and III trimesters of pregnancy, the biparietal size and head circumference, the average diameter of the chest, the diameters or circumference of the abdomen, and the length of the femur are measured, while determining the estimated weight of the fetus (Fig. 6.23).
With the use of modern ultrasound equipment, it became possible to evaluate the activity of various organs and systems of the fetus. Most congenital malformations can be diagnosed prenatally. For their detailed assessment, three-dimensional echography is used, which gives a three-dimensional image.
Ultrasound makes it possible to accurately determine the location, thickness and structure of the placenta. With real-time scanning, especially with transvaginal examination, a clear image of the chorion can be obtained from 5-6 weeks of pregnancy.
An important indicator of the condition of the placenta is its thickness with typical growth as pregnancy progresses. By 36-37 weeks, the growth of the placenta stops. In the future, during the physiological course of pregnancy, the thickness of the placenta decreases or remains at the same level, amounting to 3.3-3.6 cm.
Ultrasound signs of changes in the placenta as pregnancy progresses are determined by the degree of its maturity according to P. Grannum (Table 6.3, Fig. 6.24).
Table 6.3. Ultrasound signs of the degree of maturity of the placenta
Degree placental maturity | Chorionic membrane | Parenchyma | Basal layer |
straight, smooth | homogeneous | Not identified |
|
slightly wavy | Few echo zones | Not identified |
|
with grooves | Linear echogenic seals | Linear arrangement of small echogenic areas (basal dotted line) |
|
With depressions reaching the basal layer | Round seals with depressions in the center | Large and partially merged echogenic areas, giving an acoustic shadow |
Doppler study of blood flow in the mother-placenta-fetus system. There are quantitative and qualitative methods assessment of dopplerograms of blood flow in the studied vessel. Qualitative analysis is widely used in obstetric practice. The main value in this case is not the absolute value of the blood flow velocity, but the ratio of blood flow velocities in systole (C) and diastole (D). The most commonly used are the systolic-diastolic ratio (SDO), the pulsation index (PI), for the calculation of which the average blood flow velocity (CBR) and the resistance index (IR) are additionally taken into account (Fig. 6.25).
The greatest practical value during pregnancy is the study of uteroplacental blood flow: in the uterine arteries, their branches (spiral, arcuate, radial) and the umbilical artery, as well as fetal hemodynamics: in the aorta and cerebral vessels of the fetus. At present, the study of venous blood flow in the fetus in ductus venosus.
During uncomplicated pregnancy, peripheral vascular resistance gradually decreases, which is expressed by a decrease in blood flow indices (Table 6.4).
Table 6.4. Doppler parameters in the fetal aorta, umbilical cord artery and uterine artery in the third trimester of uncomplicated pregnancy, M±m
An increase in vascular resistance, manifested primarily by a decrease in the diastolic component of blood flow, leads to an increase in these indices.
Doppler echocardiography of the fetus is also used in obstetric practice. It has the greatest practical value in the diagnosis of congenital heart defects.
Color Doppler mapping (CDM) is a combination of two-dimensional echo-impulse information and color information about the speed of blood flow in the organs under study. The high resolution of the devices makes it possible to visualize and identify the smallest vessels of the microvasculature. This makes the method indispensable in the diagnosis of vascular pathology, in particular, for the detection of retroplacental bleeding; vascular changes in the placenta (angioma), their anastomoses, leading to reverse arterial perfusion in twins, entanglement of the umbilical cord. In addition, the method allows assessing malformations of the heart and intracardiac shunts (from the right ventricle to the left through a ventricular septal defect or regurgitation through the valve), identify the anatomical features of the fetal vessels, especially small caliber (renal arteries, circle of Willis in the fetal brain). CDI provides the possibility of studying blood flow in the branches of the uterine artery (up to the spiral arteries), the terminal branches of the umbilical artery, and the intervillous space.
Determination of the biophysical profile of the fetus. Real-time ultrasound devices allow not only to assess the anatomical features of the fetus, but also to obtain fairly complete information about its functional state. Currently, the so-called fetal biophysical profile (BFPP) is used to assess the intrauterine state of the fetus. Most authors include in this concept the data of a non-stress test and indicators determined by ultrasound scanning in real time: respiratory movements, motor activity, fetal tone, amniotic fluid volume, degree of placental maturity (Table 6.5).
Options | 2 points | 1 point | 0 points |
Non-stress test | 5 or more accelerations with an amplitude of at least 15 per minute and a duration of at least 15 s, associated with fetal movements for 20 minutes | From 2 to 4 accelerations with an amplitude of at least 15 per minute and a duration of at least 15 s, associated with fetal movements in 20 minutes | 1 acceleration or less in 20 minutes |
Fetal activity | At least 3 generalized movements within 30 minutes | 1 or 2 generalized fetal movements within 30 minutes | Absence of generalized fetal movements within 30 minutes |
Fetal respiratory movements | At least 1 episode of respiratory movements lasting at least 60 seconds in 30 minutes | At least 1 episode of respiratory movements lasting from 30 to 60 seconds in 30 minutes | No breathing or breathing less than 30 seconds in 30 minutes |
Muscle tone | 1 episode of return of fetal limbs from extended to flexed position or more | At least 1 episode of the return of the fetal limbs from extended to flexed position | Limbs in extended position |
Amount of amniotic fluid | Vertical pocket of a free area of water 2-8 cm | 2 pockets or more of amniotic fluid 1-2 cm in size | Amniotic fluid pocket less than 1 cm |
maturity placenta | Corresponds to gestational age | III degree of maturity up to 37 weeks |
The high sensitivity and specificity of BFPP are explained by a combination of markers of acute (non-stress test, respiratory movements, motor activity and fetal tone) and chronic (amniotic fluid volume, degree of placental maturity) fetal disorders. Reactive NST, even without additional data, indicates a satisfactory condition of the fetus, with non-reactive NST, ultrasound of other biophysical parameters of the fetus is indicated.
Determination of BFPP is possible already from the beginning of the III trimester of pregnancy.
Ultrasound examination of the brain (neurosonography) of a newborn. Indications for neurosonography in the early neonatal period are chronic oxygen deficiency in the prenatal period of development, birth in breech presentation, operative delivery, rapid and rapid delivery, asphyxia, as well as high or low birth weight, neurological symptoms.
The study is carried out using sectoral sensors (3.5-7.5 MHz). Special medical preparation is not required. The duration of the study is on average 10 minutes.
In an echographic examination of the brain, standard sections are sequentially obtained in the coronal and sagittal planes through the large fontanel (Fig. 6.26). Scanning through the temporal bone of the child's head allows a better assessment of the state of the extracerebral spaces. Cerebral blood flow in children is determined mainly in the anterior and middle cerebral arteries. Arteries appear on the screen as pulsating structures. Visualization is greatly facilitated by the use of color Doppler. When analyzing the curves of blood flow velocities in the cerebral vessels, the systolic-diastolic ratio and the resistance index are determined.
With neurosonography, it is possible to diagnose cerebral ischemia and edema, changes in the ventricular system of the brain, intracranial hemorrhages of various localization and severity, and malformations of the central nervous system.
Examination of amniotic fluid includes determination of quantity, color, transparency, biochemical, cytological and hormonal composition.
Determining the amount of amniotic fluid. Determining the volume of amniotic fluid with ultrasound can be subjective or objective. An experienced specialist can assess the amount of amniotic fluid with careful longitudinal scanning (a large amount of fluid between the fetus and the anterior abdominal wall of a pregnant woman with polyhydramnios, a sharp decrease in the number of spaces free from echostructures with oligohydramnios).
There are objective semi-quantitative echographic criteria for the non-invasive assessment of the amount of amniotic fluid. To do this, measure the depth of the free area of the amniotic fluid (vertical pocket), the value of which is normally from 2 to 8 cm. uterus. In a normal pregnancy, the IAI is 8.1-18 cm.
Amnioscopy- transcervical examination of the lower pole of the fetal bladder. During amnioscopy, attention is paid to the color and consistency of amniotic fluid, the admixture of meconium or blood, the presence and mobility of flakes of caseous lubricant. Indications for amnioscopy are suspicion of chronic fetal hypoxia, post-pregnancy, isoserological incompatibility of maternal and fetal blood. For amnioscopy, the pregnant woman is placed in a gynecological chair and a vaginal examination is performed to determine the patency of the cervical canal. Under aseptic conditions, a tube with a mandrel is inserted into the cervical canal through the finger or after the neck is exposed by mirrors. The diameter of the tube is selected depending on the opening of the neck (12-20 mm). After removing the mandrin and turning on the illuminator, the tube is positioned in such a way that the presenting part of the fetus is visible, from which the light beam is reflected. If the mucus plug interferes with the examination, it is carefully removed with a tupfer. With a low location of the placenta on the fetal membranes, a vascular pattern is clearly visible. Contraindications to amnioscopy: inflammatory processes in the vagina and cervix, placenta previa.
Amniocentesis- an operation, the purpose of which is to obtain amniotic fluid for biochemical, hormonal, immunological, cytological and genetic studies. The results allow us to judge the condition of the fetus.
Indications for amniocentesis are isoserological incompatibility of maternal and fetal blood, chronic fetal hypoxia (pregnancy prolongation, preeclampsia, extragenital diseases of the mother, etc.), determination of the degree of fetal maturity, antenatal diagnosis of its sex, the need for karyotyping in cases of suspected congenital or hereditary pathology of the fetus , microbiological research.
Depending on the puncture site, there are transvaginal and transabdominal amniocentesis. The operation is performed under ultrasound guidance, choosing the most convenient puncture site depending on the location of the placenta and small parts of the fetus (Fig. 6.27).
During transabdominal amniocentesis, after treatment of the anterior abdominal wall with an antiseptic, anesthesia of the skin, subcutaneous tissue and subaponeurotic space is performed with a 0.5% novocaine solution. For research take 10-15 ml of amniotic fluid. In Rh-sensitized pregnant women, when a bilirubin optical density (OPD) study is necessary, the amniotic fluid sample should be quickly transferred to a dark vessel to avoid changing the properties of bilirubin under the influence of light. Samples contaminated with blood or meconium are unsuitable for research.
Transvaginal amniocentesis is performed through the anterior vaginal fornix, cervical canal, or posterior vaginal fornix. The choice of the insertion site for the puncture needle depends on the location of the placenta. After sanitation of the vagina, the cervix is fixed with bullet forceps, shifted up or down, depending on the method chosen, and the vaginal wall is punctured at an angle to the uterine wall. When the puncture needle enters the uterine cavity, amniotic fluid begins to stand out from its lumen.
Complications that are possible with amniocentesis: premature rupture of amniotic fluid (more often with transcervical access), injury to the fetal vessels, injury to the bladder and intestines of the mother, chorioamnionitis. Complications of amniocentesis can also include premature rupture of membranes, preterm labor, placental abruption, fetal injury, and umbilical cord injury. However, due to the widespread introduction of ultrasound guidance during this operation, complications are extremely rare. In this regard, the contraindications to amniocentesis have also changed: the threat of abortion remained practically the only contraindication to it. Amniocentesis, like all invasive interventions, is performed only with the consent of the pregnant woman.
Determining the degree of maturity of the fetus. For this purpose, a cytological examination of the amniotic fluid is carried out. To obtain and study the sediment, the amniotic fluid is centrifuged at 3000 rpm for 5 minutes, the smears are fixed with a mixture of ether and alcohol, then stained according to the Garras-Shor method, Papanicolaou or, more often, 0.1% Nile blue sulfate solution. Non-nuclear lipid-containing cells (a product of the sebaceous glands of the skin of the fetus) are stained in Orange color(so-called orange cells). Their content in the smear corresponds to the maturity of the fetus: up to 38 weeks of gestation, the number of these cells does not exceed 10%, and after
38 weeks reaches 50%.
To assess the maturity of the lungs of the fetus, the concentration of phospholipids in the amniotic fluid is also determined, primarily the ratio of lecithin / sphingomyelin (L / C). Lecithin, saturated with phosphatidylcholine, is the main active principle of the surfactant. Interpretation of the value of the ratio L/S:
L / S \u003d 2: 1 or more - light mature. Only 1% of newborns are at risk of developing respiratory distress syndrome;
L / S = 1.5-1.9: 1 - development of respiratory distress syndrome is possible in 50% of cases;
L / S = less than 1.5: 1 - development of respiratory distress syndrome is possible in 73% of cases.
The method of qualitative assessment of the ratio of lecithin and sphingomyelin (foam test) has also found practical application. For this purpose, 3 ml of ethyl alcohol is added to a test tube with 1 ml of amniotic fluid and within
Shake the tube for 3 minutes. The resulting ring of foam indicates the maturity of the fetus (positive test), the absence of foam (negative test) indicates the immaturity of the lung tissue.
Diagnosis of outflow of amniotic fluid. One of the methods for diagnosing the outflow of amniotic fluid during pregnancy is a cytological examination of fresh stained preparations. A drop of vaginal contents is applied to a glass slide, a drop of 1% eosin solution is added and covered with a coverslip. Under a microscope on a pink background, brightly colored epithelial cells of the vagina with nuclei, erythrocytes, leukocytes are visible. When the waters have broken, large accumulations of uncolored "scales" of the skin of the fetus are visible.
In recent years, in order to diagnose prenatal rupture of amniotic fluid, the amnio test is widely used - special swabs soaked in a reagent that change color when in contact with amniotic fluid.
X-ray examination. In connection with negative impact ionizing radiation on the embryo and fetus X-ray examination is rarely used. At the end of pregnancy, the radiosensitivity of the fetus decreases, X-ray studies at this time are less dangerous. In obstetric practice, to clarify changes in the bone pelvis, X-ray pelvimetry is sometimes used, which allows you to determine the shape and true dimensions of the small pelvis.
Indications for X-ray pelviometry: suspicion of mismatch between the size of the pelvis of the mother and the head of the fetus, anomalies in the development of the pelvis, spinal injuries.
Produce direct and lateral pictures of the pelvis. On a radiograph taken in direct projection, the transverse size of the pelvis and the fronto-occipital size of the head are measured. On the lateral radiograph, the true conjugate and the large transverse size of the head are determined. The shape and dimensions of the sacrum on the radiograph are characterized by the length of its chord, the angle of the sacral curvature and the magnitude of its radius. To assess the sacrum, the sacral index is used, which is calculated as the ratio of the length of the chord of the sacrum to the radius of the sacral curvature. The sacral index reflects the length of the sacrum and the severity of its curvature. The definition of flattening of the sacrum is an important feature for predicting the nature of the birth act.
X-ray pelviometry data allow you to clarify the shape of the narrow pelvis and accurately determine the degree of narrowing.
Determination of tissue pO 2in the fetus. Oxygen tension (pO2) in the tissues of the fetus can be determined by the polarographic method during childbirth in the absence of a fetal bladder. This provides an early diagnosis of intrauterine fetal hypoxia. You can apply the intra- and transdermal polarographic method. For intradermal determination of pO2, open microelectrodes are used, which are easily and without complications introduced into tissues. Interstitial polarographic determination has a well-known advantage, since the electrodes respond faster to changes in pO2 and have less inertness than electrodes for transcutaneous measurement.
The working needle electrode is inserted under the skin of the fetal head to a depth of 0.5-0.6 mm after the outflow of amniotic fluid and the opening of the cervix to
4 cm or more, the reference electrode is inserted into the posterior fornix of the vagina.
Study of the blood of the fetus and newborn. The most important information about the condition of the fetus can be given by the results of a direct study of its blood obtained from the umbilical cord or head.
Cordocentesis. Blood is obtained from the vein of the umbilical cord by intrauterine puncture under ultrasound control (Fig. 6.28).
The method is indicated for diagnosing congenital and hereditary pathologies (fetal karyotyping), intrauterine infection, fetal hypoxia, its anemia during immunoconflict pregnancy. In addition to a wide range of diagnostic tasks, cordocentesis also allows solving some important problems of intrauterine therapy in fetal hemolytic disease.
Cordocentesis is performed after 18 weeks of pregnancy. Before taking the blood of the fetus, the localization of the placenta and the place of origin of the umbilical cord are established. When the placenta is located on the anterior wall of the uterus, the needle for blood aspiration is carried out transplacentally, in the case of localization of the placenta on the posterior wall, the needle is inserted transamnionally. The umbilical cord is punctured near the place of its discharge from the placenta. With high motor activity of the fetus, which interferes with the puncture, intramuscular or intravenous administration of drugs to the fetus is recommended to ensure its short-term complete immobilization. To do this, use the muscle neuroblocker pipecuronium (arduan) at a dose of 0.025-0.25 mg/kg. The volume of the blood sample depends on the indication for cordocentesis; usually no more than 2 ml is required.
The risk of complications during cordocentesis for a pregnant woman is low. Complications for the fetus include premature outflow of water (0.5%), bleeding from a punctured vessel (5-10%), as a rule, not prolonged and not life-threatening for the fetus. Perinatal losses do not exceed 1-3%. Contraindications for cordocentesis are the same as for amniocentesis.
Determination of the acid-base state (CBS) of the blood. During childbirth, capillary blood from the fetus is obtained from the presenting part according to the Zaling method. For this purpose, after the outflow of amniotic fluid, a metal amnioscope tube with fiber optics is inserted into the birth canal. At the same time, the area of the presenting part of the head or buttock is clearly visible, the skin of which is wiped with a gauze swab in order to create hyperemia. A special scarifier is used to puncture the skin to a depth of 2 mm, after which blood is collected (except for the first drop) in a sterile heparinized polyethylene capillary without air layers and amniotic fluid impurities. The study of blood microdoses allows you to quickly obtain information about the state of the fetus, but the method is very laborious and not always feasible.
To determine the CBS of blood in a newborn, blood is taken from the vessels of the umbilical cord immediately after birth or capillary blood is used from the heel of the child.
In the study of CBS of blood, the value of pH, BE (deficiency of bases or excess of acids), pCO2 (partial tension of carbon dioxide), pO2 (partial tension of oxygen) are taken into account.
Biopsy (aspiration) of chorionic villi - an operation, the purpose of which is to obtain chorionic villous cells for fetal karyotyping and determination of chromosomal and gene anomalies (including the determination of hereditary metabolic disorders), as well as to determine the sex of the fetus. Samples are taken transcervically or transabdominally at 8-12 weeks of gestation under ultrasound control. A sterile polyethylene flexible catheter 26 cm long and 1.5 mm in outer diameter is inserted into the uterine cavity and carefully advanced under visual control to the placenta localization site and further between the uterine wall and placental tissue. Then, with a syringe with a capacity of up to 20 ml, containing 3-4 ml of nutrient medium and heparin, chorionic tissue is aspirated, which is then examined (Fig. 6.29). You can take samples of chorionic tissue in multiple pregnancies.
Complications of chorionic villus biopsy are intrauterine infection, bleeding, spontaneous miscarriage, and hematoma formation. Late complications include premature birth, low birth weight of newborns (less than 2500 g), fetal malformations. Perinatal mortality reaches 0.2-0.9%. Contraindications for chorionic biopsy may include genital tract infection and symptoms of threatened miscarriage. Placentocentesis may be performed later in pregnancy.
Fetoscopy(direct examination of the fetus) is used to detect congenital and hereditary pathologies. The method allows you to examine parts of the fetus through a thin endoscope inserted into the amniotic cavity, and take blood and epidermis samples for examination through a special channel. Fetoscopy is carried out as one of the final stages of the examination in cases of suspected congenital anomalies of the fetus.
Fetoscope insertion technique: after appropriate treatment of the skin under local anesthesia under sterile conditions, a small skin incision is made and the trocar, located in the cannula, is inserted into the uterine cavity. Then it is removed, a sample of amniotic fluid is obtained for examination, an endoscope is inserted into the cannula and a targeted examination of the fetus is carried out. If necessary, take a blood sample or biopsy of the skin of the fetus. At the end of the operation, cardiomonitoring of the fetus is carried out; the pregnant woman remains under observation for 24 hours.
Complications of fetoscopy include rupture of amniotic fluid, termination of pregnancy. Complications such as bleeding and the development of infection, the formation of small superficial hematomas on the limbs of the fetus, are extremely rare. Due to the possibility of termination of pregnancy, fetoscopy is rarely used.
Study of the hormonal profile. Biological methods for diagnosing pregnancy, based on the reaction of animals to the administration of the patient's urine, containing or not containing XE, have now lost their leading role. Preference is given to immunological methods.
Immunological methods for diagnosing pregnancy. The immunological ones are various methods determination of chorionic gonadotropin (CG) or its b-subunit (b-CG) in blood serum and urine. Preference is given to the radioimmunological method for the quantitative determination of b-CG in blood serum, since it has a high specificity and sensitivity. Enzyme immunoassay methods for detecting hCG in the urine, as well as other variants of immunological tests (capillary, plate) deserved a positive assessment. Have the right to exist and such well-known serological methods for determining hCG in the urine, such as the reaction of inhibition of agglutination of erythrocytes or the deposition of latex particles.
Agglutination, or latex particle fixation test, is a method for determining the level of hCG in the urine, which is excreted in the urine 8 days after fertilization. A few drops of the patient's urine are mixed with CG antibodies, then CG-coated latex particles are added. If hCG is present in the urine, it binds to antibodies; if hCG is absent, then the antibodies bind to the latex particles. This rapid test is positive in 95% of cases, starting from the 28th day after fertilization.
radioimmunoassay test. The content of the b-subunit of hCG in the blood plasma is determined.
Screening - a system of activities and medical research, tests and procedures aimed at the preliminary identification of persons among whom the likelihood of a certain disease is higher than that of the rest of the population being examined. Screening is a preliminary stage of the examination, persons with a positive screening result need an additional examination to establish or exclude pathology.
Basic concepts of any screening:
screening test sensitivity - the ability to detect individuals with the disease being screened;
the specificity of a screening test is the ability to correctly identify individuals who do not have the disease.
In the absence of a combination between the test results and the disease in the patient, false negative and false positive results are determined. The probability of a disease given a known test result is called its predictive value.
With each pregnancy, there is a possibility of malformations and / or chromosomal pathology in the fetus. The baseline risk of chromosomal abnormality of the fetus depends on the age of the woman, and the individual risk is calculated by multiplying the baseline risk by the likelihood ratios of the screening tests performed in this pregnancy.
In developed countries, there are various schemes of prenatal screening, based mainly on biochemical parameters and echography. Using only these technologies with further confirmation makes it possible to reduce the number of births of children with hereditary and congenital fetal pathology by approximately 30%. It should be emphasized that the effectiveness of such studies is proportional to the completeness of their coverage of pregnant women. It has been shown that with full coverage it is possible to reduce the frequency of chromosomal pathology by 40-45%, neural tube defects - by 85-90%. Screening of the first and second trimesters is distinguished.
In this case, it should be emphasized that the national project Health and population policy in section No. 1 On the program for prenatal (prenatal) diagnosis of developmental disorders of the child ... provides for the transfer of all activities for prenatal diagnosis from the II to the I trimester, so screening of the I trimester should be a priority.
Screening in the first trimester
Existing on present stage screening of pregnant women in the first trimester is based on ultrasound data and the determination of maternal serum markers [pregnancy-associated plasma protein A (PAPP-A) and free p-subunit of chorionic gonadotropin] with subsequent software complex calculation of the individual risk of having a child with a chromosomal pathology (order of the Ministry of Health of Russia dated November 12, 2012 No. 572n). To undergo screening, a pregnant woman at a gestational age of 11-14 weeks is sent to a medical organization that provides an expert level of prenatal diagnosis for a comprehensive prenatal (prenatal) diagnosis of developmental disorders of the child.
When interpreting the results of the study of biochemical markers, it is taken into account that their quantitative fluctuations may depend on the patients belonging to different populations and ethnic groups, on the research method. That is why individual results are evaluated using MoM (Multiple of Median) - the ratio of the individual marker value to the median determined for a given population. It is generally accepted that the normal values of biochemical markers fall within the range of 0.5-2.0 MoM.
Pregnancy-associated PAPP-A is secreted by the trophoblast. Its concentration does not depend on the sex and weight of the child, it increases depending on the duration of pregnancy. With chromosomal abnormalities in the fetus, its concentration is significantly reduced, and this decrease is most pronounced at the 10-11th week of pregnancy (about 0.5 MoM). The most noticeable decrease in the concentration of PAPP-A is observed with trisomies 21, 18 and 13, to a lesser extent - with aneuploidies for sex chromosomes. A decrease in the concentration of PAPP-A is also noted in cases not associated with fetal chromosomal pathology - with spontaneous abortions, premature births, etc. Human chorionic gonadotropin is produced by any type of trophoblastic tissue, including hydatidiform mole, chorionadenoma and chorioncarcinoma. With trisomy 21 (Down syndrome) in the fetus, the concentration of the free chain of hCG increases significantly (about 2 MoM), and with trisomy 18 (Edwards syndrome) it decreases.
Among the many echographic markers of fetal chromosomal pathology highest value has an increase in the thickness of the collar space. The optimal time for measuring the thickness of the collar space is 11-14 weeks of gestation. The thickness of the collar space increases with the increase in the coccygeal-parietal size of the fetus, therefore, for each coccygeal-parietal size of the fetus, there are median and 95% centile values. To assess this indicator, both modern ultrasonic devices and highly qualified specialists are needed. An increase in the thickness of the collar space is combined with an increased risk of trisomies 21, 18, Turner syndrome, and many other chromosomal and non-chromosomal syndromes.
Screening in the second trimester
As screening markers of the second trimester of pregnancy in a number of countries, p-fetoprotein, human chorionic gonadotropin and unconjugated estradiol are used for a period of 15-20 weeks. According to a number of data, screening of the second trimester is the least accurate, leading to the largest number of unreasonable invasive diagnostic procedures. In the case of screening of the first trimester, the determination of biochemical markers of the second trimester is not required, and in the absence of screening of the first trimester, it is possible at the request of the family. According to the order of the Ministry of Health of Russia No. 572n, screening of the second trimester (18-21 weeks of pregnancy) includes only ultrasound to exclude late-manifesting congenital anomalies in the development of the fetus.
Not a single change in screening tests can be considered as an indication for termination of pregnancy, as well as for the appointment of additional examinations for fetal chromosomal pathology. To determine the individual risk of chromosomal abnormalities in the fetus, there is special software. In Russia, both foreign programs for calculating individual risk - LifeCycle (Finland), ASTRAIA (Germany), PRISCA (Germany), and a number of domestic ones - PROGNOS (Moscow), ISIDA (St. Petersburg) and PRESCREEN (Novosibirsk) are widespread. Most of all, the ASTRAIA program stands out, which is designed for screening of the first trimester, provides for a risk threshold of 1/100, corresponding to the threshold risk by order of the Ministry of Health of Russia No. 572n and includes control of measurement of indicators during ultrasound and ongoing audit. If a pregnant woman is at high risk for chromosomal abnormalities in the fetus (individual risk is 1/100 and higher), as well as if congenital anomalies (malformations) are detected in the fetus in any trimester of pregnancy, the obstetrician-gynecologist sends the woman to a medical genetic consultation for addressing the issue of conducting confirmatory diagnostics using invasive examination methods. In the case of a diagnosis in the fetus, further tactics of pregnancy management are determined by the perinatal consultation of doctors.
DNA SCREENING NEUPLOYID
In recent years, methods for non-invasive prenatal DNA screening of fetal aneuploidy by maternal blood have been developed and are being introduced into clinical practice, based on the analysis of extracellular fetal DNA circulating in the mother's bloodstream in sufficient quantities for analysis already from 10-11 weeks of gestation.
Currently, DNA screening is carried out for the most common chromosomal aneuploidies of the fetus - trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), trisomy 13 (Patau syndrome), as well as numerical disorders of the sex chromosomes leading to the emergence of Turner syndromes (monosomy on the X chromosome in female fetuses) and Klinefelter (the presence of two X chromosomes in male fetuses). At the same time, the sensitivity and specificity of DNA screening are superior to all other screening methods and, in particular, for trisomy 21 reach 99% and 99.9%, respectively. Similar indicators for other chromosomes are in the range of 90-99.9%. Potentially, DNA screening has the ability to detect chromosomal microdeletions and microduplications, however, at the moment, such studies are not sufficiently validated, and therefore their appointment seems inappropriate. The main advantages of non-invasive prenatal DNA screening for aneuploidy:
safety for mother and fetus - only a sample of venous blood of a pregnant woman (9-20 ml) is needed for analysis;
high efficiency in identifying women at risk of aneuploidy in the fetus;
the possibility of conducting a study in the first trimester of pregnancy.
Limitations and disadvantages of non-invasive prenatal DNA screening for aneuploidy:
there is no information about the complete karyotype, structural abnormalities of chromosomes, chromosomal mosaicism, monogenic diseases;
uninformative in multiple pregnancies, as well as self-reduction of fetuses in the early stages of pregnancy;
limited use during pregnancy resulting from IVF using a donor egg and in surrogate motherhood;
relatively high cost and duration. Maternal DNA screening is intended to identify women at high risk of fetal aneuploidy and does not replace invasive diagnostic tests. In the case of detection of chromosomal disorders using DNA screening on the mother's blood, confirmatory diagnostic invasive procedures are necessary. Biochemical analysis of alpha-fetoprotein cannot be replaced by maternal DNA screening, as it allows the detection of a wider range of fetal malformations, including neural tube defects not associated with chromosomal aneuploidy and abdominal wall malformations.
Despite the current limitations, as it develops, non-invasive prenatal DNA screening for aneuploidy has the potential to become the basis of screening programs in the first trimester. The introduction of this technology as a routine screening of pregnant women can make a breakthrough in helping pregnant women and significantly reduce the number of newborns with chromosomal disorders.
These methods are more dangerous in terms of possible complications and more time-consuming to carry out, so the doctor prescribes them only for severe indications.
Invasive prenatal diagnosis 1 is divided into several types. Her task is to obtain a tissue sample belonging to the fetus.
Who is prescribed invasive diagnostics?
The risk of developing chromosomal and genetic diseases is increased in the following cases:
- mother's age is 35 years and older;
- the birth of a child with a chromosomal pathology in the family;
- identification of carriers of a family chromosomal anomaly;
- monogenic diseases that were previously identified in the family and close relatives;
- if before pregnancy or at its early stage, a woman took a number of pharmacological drugs (anticancer and others);
- transferred viral infections(hepatitis, rubella, toxoplasmosis and others);
- irradiation of one of the spouses before conception;
- having at least two spontaneous abortions early dates pregnancy in the past.
These women, as well as all pregnant women, undergo non-invasive prenatal diagnosis. These are screening biochemical tests: double - at 11-13 weeks (biochemical blood test + ultrasound) and triple, as well as quadruple (with inhibin A) tests at 16-18 weeks. If the results of screening studies are alarming and the woman is at risk, the doctor determines the need for invasive procedures.
If a woman is not at risk, but the results of tests and ultrasound turned out to be doubtful, then she is also prescribed one of the methods of invasive diagnostics.
The decision to conduct the study is made by the family based on the information provided by the doctor. The doctor recommends a study only if the risk of severe disease in the fetus outweighs the risk of complications from an invasive diagnosis. At the same time, the “prices” of risks, which are different in different cases, are also taken into account. For example, a 7% risk for a woman with three children, and the same risk for a woman who has no children (this pregnancy is the first after 10 years of infertility or previous pregnancies ended in miscarriages) will be estimated differently.
Contraindications for amniocentesis, chorionic villus sampling
Contraindications to conducting invasive studies are relative, that is, even if there are contraindications, it may be possible and necessary to conduct a study. So, among the contraindications is the threat of abortion, but it is known that such a threat often occurs in the presence of certain fetal malformations, and the study is necessary to determine the further tactics of pregnancy, and to maintain the pregnancy, the study is carried out against the background of appropriate therapy.
Contraindications may also be uterine malformations, high fever, active infectious diseases, fibroid nodes - a benign muscle tissue tumor located in the path of needle insertion, as well as the location of the placenta in the path of needle insertion.
How is amniocentesis and chorionic villus sampling performed?
Invasive studies are usually performed on an outpatient basis. In this case, it is necessary to have the results of laboratory tests (blood and urine tests, tests for syphilis, AIDS, hepatitis B and C, analysis of a vaginal smear, and others - according to indications).
An experienced specialist should carry out invasive manipulations. Examinations are carried out under local anesthesia under the control of an ultrasound image. A puncture is performed) of the anterior abdominal wall or access is made through canal B of the cervix: the choice depends on the placenta attachment in the uterus. Further, without touching the fetus, material is taken for research - particles of chorionic villi or placenta, amniotic fluid or blood from the umbilical vein. The fetus is not touched during invasive examinations, unless the purpose of the examination is a biopsy of fetal tissues! Further, the pregnant woman remains under the supervision of specialists for some time (4-5 hours). To prevent possible complications, a woman may be prescribed special medications. If during the observation certain complications are noted: there is a threat of termination of pregnancy, placental abruption, etc., then the woman is hospitalized in a hospital and the complications are treated.
Types of invasive diagnostics
There are the following types of invasive prenatal diagnostics:
- chorionbiopsy (biopsy of chorionic villi);
- placencentesis;
- amniocentesis;
- cordocentesis;
- biopsy of fetal tissue.
Chorionic villus biopsy
It allows you to conduct research on the chromosome set of the fetus (for example, the diagnosis of Down syndrome, Edwards, Patau) and gene mutations. The first method of conducting the study involves vaginal access: under ultrasound control, a catheter (a thin tube) is inserted through the cervix to the fetal egg. After contact with the chorion, a certain amount of chorion tissue is sucked with it. The second way to take chorionic tissue - abdominal - with a syringe through the anterior abdominal wall. Such a study is also carried out under the control of ultrasound. A chorionic villus biopsy is performed at 11-12 weeks of gestation.
The result of the analysis is known 3-4 days after taking the material. Since the study is carried out up to 12 weeks of pregnancy, if necessary, termination of pregnancy is also carried out up to 12 weeks, which is the safest for the woman's body.
When performing a chorion biopsy, there is a risk of false positive or false negative results, which is explained by the phenomenon of "placental mosaicism" - the non-identity of the genome of embryonic and chorion cells.
There is also the risk of miscarriage, the risk of bleeding in a woman, the risk of infection of the fetus, as well as the risk of an unfavorable course of pregnancy with Rh conflict. When Rh-conflict in the body of a Rh-negative mother, antibodies are produced that destroy the red blood cells of the fetus. Performing a chorionic biopsy can stimulate the production of antibodies.
It should be noted that in general, the risk of all these complications is small: it is no more than 2%.
Placentocentesis
Placentocentesis(placental biopsy) is the taking for examination of a sample of placental particles containing fetal cells, and hence all of its chromosomal genetic material. Placentocentesis is similar to a chorionic biopsy, because the placenta is what the chorion develops over time, however, it is carried out at a later date - 12-22 weeks of pregnancy. The analysis is being prepared for several days. The main task of placentocentesis is to identify chromosomal and gene diseases in the fetus.
Under ultrasound control, the doctor punctures the woman's anterior abdominal wall with a needle and takes a piece of the placenta for further examination. Since the study is carried out in the second trimester of pregnancy, if a pathology is detected, termination of pregnancy is more traumatic than early terms.
Complications of placentocentesis may be placental abruption, the threat of abortion, but their likelihood is minimal.
Amniocentesis
Amniocentesis is a method of obtaining amniotic fluid. This method makes it possible to determine a larger number of indicators. In addition to gene and chromosomal diseases, it is possible to determine biochemical indicators (metabolism indicators), which can be used to judge possible metabolic disorders, the presence of certain diseases. For example, with the help of amniocentesis, the degree of maturity of the fetal lungs (retention of lecithin and sphingomyelin), the presence of hypoxia (oxygen starvation), Rh conflict is determined - a condition in which antibodies to Rh-positive erythrocytes of the fetus are produced in the body of an Rh-negative mother, while erythrocytes the fetus is destroyed and the decay products of erythrocytes enter the amniotic fluid.
The study is possible from 15-16 weeks of pregnancy. Under ultrasound control, a syringe is inserted into the uterine cavity through the anterior abdominal wall, into which a material of 20-30 ml is collected. In addition to the amniotic fluid itself, a small amount of fetal cells (thickened epithelium) also enter the syringe, which are also examined.
The result of the analysis after amniocentesis is ready in 2-3 weeks (special nutrient media are required for execution, since there are few cells obtained and they need to multiply, as well as certain development methods and a sufficient amount of time).
Among the possible complications are abortion, leakage of amniotic fluid, infectious complications, bloody discharge from the genital tract, worsening of the Rh conflict. The likelihood of complications in this study is less than when performing a biopsy of the chorion.
Cordocentesis- This is a puncture of the vessels of the umbilical cord. The material is taken by puncturing the anterior abdominal wall of the pregnant woman (under ultrasound control) and obtaining cord blood. The study is carried out after the 20th week of pregnancy. Cordocentesis allows you to perform almost all the tests that can be done from a regular blood test (hormonal examination, biochemical parameters, infections, immunological conditions, etc.), and, like all other methods, it helps to identify gene and chromosomal diseases. This method is used not only as a diagnostic procedure, but also as a therapeutic one - for the administration of medicines, intrauterine blood transfusion to the fetus - for example, in severe Rh conflict.
With the help of amniocentesis and cordocentesis, infections can also be diagnosed (if infection is suspected). Termination of pregnancy can also become a complication of the procedure.
Fetal tissue biopsy as a diagnostic procedure carried out in the second trimester of pregnancy under ultrasound control. To diagnose severe hereditary skin diseases (hyperkeratosis, ichthyosis - diseases in which the process of keratinization of the skin is disturbed, the surface layer of the skin thickens, the skin becomes similar to fish scales), a biopsy of the fetal skin is taken. The technique for obtaining the material is similar to that described above, but at the end of a special needle that is inserted into the uterine cavity, there are tweezers that allow you to get a small area of fetal skin. Next, a study is conducted that allows you to clarify the presence of hereditary skin diseases. To diagnose muscle diseases, a biopsy of the fetal muscles is performed.
How is the material used? The tissue obtained as a result of a particular procedure is used for research. We list the main types:
cytogenetic- using this method, the presence of additional or missing chromosomes is determined (detection of Down's syndrome - an extra 21st chromosome, Klinefelter's - an extra X chromosome, Turner's syndrome - a lack of an X chromosome in a female fetus).
Molecular genetic- using this method, the presence of defects inside the chromosomes is determined, that is, the presence of gene mutations that cause certain diseases: hemophilia, phenylketonuria, Duchenne muscular dystrophy, cystic fibrosis.
Biochemical(determining the degree of maturity of the lungs of the fetus, fetal hypoxia) and others (determining the presence and severity of the Rhesus conflict).
Subject to compliance with all the rules and regulations for invasive diagnostics, the main risk of the listed procedures is the threat of miscarriage. In quantitative terms, it is 2-3%. But these figures do not exceed the risk of the same problem in other pregnant women. Meanwhile, the result obtained is extremely important for predicting the health of the unborn child, because these diagnostic methods are the most accurate.
1 Prenatal diagnosis (pre - “before”, natalis - “relating to childbirth”) allows you to establish the condition of the fetus before childbirth.
2 Chorion is the precursor of the placenta, it is attached to the wall of the uterus.
In a number of cases, invasive diagnostic methods are used to assess the nature of the course of pregnancy and the condition of the fetus, some of which are performed with echographic control.
A significant part of prenatal invasive studies is cytogenetic diagnosis of chromosomal diseases. In these cases, the indications for its implementation are: the age of the mother is 35 years and older; the birth of a child with a chromosomal pathology in the family; carriage of a family chromosomal anomaly; suspicion of the presence of congenital malformations in the fetus; the presence of echographic signs of chromosomal pathology; deviation of levels of serum maternal markers.
The choice of the method of invasive diagnostics is determined by the relevant indications, the gestational age, the condition of the pregnant woman, and her consent is also taken into account.
In the first trimester of pregnancy, transcervical or transabdominal aspiration of chorionic villi is most often performed. In the II trimester, amniocentesis, transabdominal aspiration of placental villi and transabdominal cordocentesis (puncture of the umbilical cord vessels) are performed.
Invasive interventions are carried out in the presence of the results of a gynecological examination of a pregnant woman and laboratory data (blood and urine tests, tests for syphilis, HIV, hepatitis B and C, analysis of a vaginal discharge smear, etc. - according to indications).
4.8.1. Examination of amniotic fluid
Determination of such characteristics of amniotic fluid as quantity, color, transparency, cytological and biochemical composition, hormone content, in some cases is of great diagnostic importance for assessing the nature of the course of pregnancy and the condition of the fetus.
The volume of amniotic fluid can be determined using both clinical research methods (measuring the circumference of the abdomen and the height of the uterine fundus, palpation), and using ultrasound diagnostics. When using these methods, the most accurate results indicating an abnormal amount of amniotic fluid can be obtained with severe oligohydramnios or polyhydramnios.
In borderline situations, manifested by relative or moderate oligohydramnios or polyhydramnios, the assessment of the volume of amniotic fluid is largely subjective. Even with ultrasound with the calculation of the amniotic fluid index, the diagnostic value of the method is low.
If an abnormal amount of amniotic fluid is suspected, an important diagnostic criterion is dynamic control over the rate of change in their amount.
With the help of amnioscopy, a transcervical examination of the lower pole of the fetal bladder is performed, which makes it possible to determine the color of the amniotic fluid, their consistency, to identify the admixture of meconium or blood, the presence of flakes of cheese-like lubricant. The indications for this diagnostic procedure are the suspicion of chronic fetal hypoxia, postnatal pregnancy, isoserological incompatibility of the blood of the mother and fetus. Contraindications include inflammatory diseases of the vagina and cervix, placenta previa.
Amniotic fluid can be obtained for biochemical, hormonal, immunological, cytological or genetic studies using amniocentesis.
Amniocentesis. Transabdominal access." />
Rice. 4.42. Amniocentesis. transabdominal access.
1 - cervix; 2 - vagina; 3 - amniotic fluid; 4 - uterus; 5 - placenta.
The indications for this diagnostic procedure are most often the need for cytogenetic diagnosis of chromosomal diseases. In more rare cases, amniocentesis is performed with fetal hypoxia, isoserological incompatibility of maternal and fetal blood, to assess the degree of fetal maturity (by the ratio of the concentration of lecithin and sphingomyelin or by the number of non-nuclear lipid-containing "orange" cells), the need for microbiological examination of amniotic fluid. Contraindications - the threat of abortion and infection of the genital tract. The procedure is performed under ultrasound guidance, choosing access depending on the location of the placenta and fetus. In this case, both transabdominal (Fig. 4.42) and transcervical amniocentesis are performed.
Among the complications of this manipulation are premature rupture of amniotic fluid, premature birth, injury to the fetus, placental abruption, damage to the umbilical cord, injury to the bladder and intestines of the mother, chorioamnionitis.
4.8.2. Fetal blood test
The results of a study of the blood of the fetus, obtained from the umbilical cord or from the vessels of the skin of the head, provide reliable and important information about its condition.
Blood from the vessels of the umbilical cord is obtained by transabdominal cordocentesis, which consists in puncturing the vessels of the umbilical cord under echographic control.
Indications for performing this diagnostic procedure are the need to diagnose chromosomal diseases in the fetus by karyotyping, suspicion of intrauterine infection, fetal hypoxia, isoserological incompatibility of maternal and fetal blood. Cordocentesis is performed after 18 weeks of pregnancy. Contraindications are the same as for amniocentesis.
Among the complications, the most common are premature rupture of amniotic fluid, premature termination of pregnancy, bleeding from a punctured vessel.
During childbirth, to study the capillary blood of the fetus, it is obtained from the vessels of the skin of the head using an amnioscope. In the obtained blood sample, the pH value (concentration of free hydrogen ions) is evaluated. With a pH value of more than 7.25, it is considered that the fetus does not suffer from hypoxia and its condition is qualified as normal. If the pH value is in the range from 7.20 to 7.24, then it is considered that the fetus is experiencing moderate hypoxia and measures must be taken to increase the degree of its oxygenation. A pH value below 7.20 indicates severe fetal hypoxia, accompanied by metabolic acidosis, which requires emergency delivery.
4.8.3. Oxygen saturation of the fetus during childbirth
One of the modern objective and safe methods for assessing the functional state of the fetus during childbirth is pulse oximetry, which is a non-invasive method for the continuous determination of fetal oxygen saturation (SpO2), which reflects the saturation of arterial blood hemoglobin with oxygen.
The saturation value is expressed as a percentage of the level of oxyhemoglobin to the sum of the concentrations of oxyhemoglobin and deoxygenated hemoglobin (with the exception of carboxyhemoglobin and methemoglobin):
AT modern appliances the technique for determining the saturation value is based on two principles. First, oxyhemoglobin and deoxygenated hemoglobin have different ability to absorb and reflect light depending on its wavelength. In the sensors used, the LEDs emit alternately red and infrared light, which have different wavelengths.
Secondly, the volume of arterial blood in the tissues and, accordingly, the ability to absorb light by the blood changes due to its pulsation due to heartbeats. During systole, due to an increase in blood volume in the tissue, the absorption of light increases, and in diastole, accordingly, it decreases. In this case, the amount of reflected light also changes inversely.
In the devices used for research, the pulse oximeter sensor must be in direct contact with the skin of the fetus. The photodetector of the sensor, located in the same plane as the light emitting elements, measures the reflected light, the magnitude of which is inversely related to the amount of absorbed light.
By analyzing the characteristics of the red and infrared light reflected from the blood flow located under the sensor, the pulse oximeter estimates the amount of saturation during the study.
Modern pulse oximeters are calibrated to standards for saturation values measured in fetal blood samples during labor, which reliably reflect fetal hypoxia.
Pulse oximetry is used in childbirth with cephalic presentation of the fetus, the absence of a fetal bladder and the opening of the cervix by at least 3 cm. Contraindications to the use of the technique are bloody discharge from the genital tract, placenta previa, multiple pregnancy, the presence of infections, a scar on the uterus.
Before the start of the study, the pulse oximeter sensor inserted into the uterine cavity is placed on the cheek of the fetus or in the temporal part, free from hair, which eliminates the distortion of the reflected light signal.
The curved shape of the working surface of the sensor and the pressure from the walls of the uterus allow it to be tightly fixed on the fetal head at the site of application. At the same time, the sensor does not injure the tissues of the mother's birth canal and fetal tissues. SpO2 registration time is 60 minutes or more. In some cases, the sensor may be poorly held between the fetal head and the inner surface of the uterine wall if the fetal head is inserted incorrectly.
In the normal course of childbirth, the saturation value varies on average from 45 to 65% and gradually decreases by 5-10% from their beginning to completion.
In this case, certain changes in the saturation value occur depending on the phases of uterine contraction. The highest SpO2 values are recorded in the pause between uterine contractions. At the beginning of the contraction, there is a slight decrease in the saturation value, followed by an increase at the peak of the contraction (comparable to the SpO2 value between contractions) and a significant decrease at the end of the contraction.
The nature of changes in the value of saturation during contractions is due to a number of factors: changes in hemodynamics in the uterine arteries and in the arteries of the umbilical cord, changes in the value of intrauterine pressure, changes in the heart rate of the fetus.
With fetal hypoxia, saturation indicators on average decrease by 15-20% compared to the norm. The degree of decrease in fetal saturation during childbirth is directly dependent on the severity of hypoxia.
In violation of the condition of the fetus, there is also a pattern of changes in the SpO2 value depending on the phases of uterine contraction. The decrease in the SpO2 value, noted at the beginning of the contraction, becomes most pronounced at the peak of uterine contraction, followed by an increase as the uterus relaxes. The more pronounced hypoxia, the lower the SpO2 value at the peak of contraction. Such changes are an unfavorable prognostic sign associated with a high risk of complications of hypoxic genesis in the fetus.
The method of fetal pulse oximetry has a number of advantages compared to other methods for assessing the condition of the fetus during childbirth, as it responds faster to changes in the oxygen content in the fetal blood. However, pulse oximetry is most appropriate to use if, according to CTG, there are signs indicating severe fetal disorders. Saturation less than 30% is a critical value for the fetus.
A rapid decrease in saturation to less than 30%, especially in combination with adverse signs of CTG (bradycardia, decreased basal rate variability, deep late decelerations), is an indication for emergency abdominal delivery. However, if possible, it is advisable to assess the pH value of the blood from the vessels of the skin of the fetal head. If at the same time the pH value is more than 7.25, then it is possible to continue the management of childbirth through the natural birth canal. At a pH of 7.24-7.20 and below, emergency abdominal delivery is necessary.
If, against the background of adverse signs of CTG, the saturation value is more than 30%, then in fact there is an adequate supply of oxygen to the fetus and it does not experience hypoxia.
There is a clear relationship between the degree of saturation of hemoglobin with oxygen in the arterial blood of the fetus during childbirth and the state of the newborn. Low levels of FSpO2 (less than 30%) also correlate with low blood pH levels in newborns (pH with an increase in base deficiency (BE) and a decrease in the number of buffer bases (BB), which together indicate hypoxia in newborns, accompanied by metabolic acidosis. Indicators of KOS and gas blood composition in newborns indicates the degree of hypoxia in the intranatal period, which is confirmed by a low Apgar score at birth and clinical manifestations of complications of hypoxic genesis.
Consequently, the results of fetal pulse oximetry allow not only to timely resolve the issue of labor management tactics and choose best way delivery, but also to predict perinatal outcomes.
The pulse oximetry method is easy to use and can be used in obstetric institutions of any level. The use of fetal pulse oximetry does not increase the risk of intrauterine infection of the fetus and does not increase the incidence of postpartum pyoinflammatory complications in puerperas.
4.8.4. Chorionic villus biopsy
With the help of this diagnostic procedure, chorionic villous cells are obtained for fetal karyotyping, if necessary, cytogenetic diagnosis of chromosomal diseases, as well as for determining the sex of the fetus. Manipulation is carried out both transcervically and transabdominally in the early stages of pregnancy (10-14 weeks) or transabdominally at 20-24 weeks under echographic control. Taking chorionic tissue is carried out by aspiration. Contraindications are the threat of abortion and infection of the genital tract.
Among the complications are bleeding, the formation of subchorial hematomas, abortion, intrauterine infection.
4.8.5. Fetoscopy
To clarify the presence of an anomaly in the development of the fetus by directly examining it, fetoscopy is used. Using this method, through an endoscope inserted transabdominally into the amniotic cavity, parts of the fetus are examined and, if necessary, samples of amniotic fluid, blood, or tissues of the fetus are taken. Contraindications - the threat of abortion and intrauterine infection.
Among the complications of fetoscopy are untimely rupture of amniotic fluid, premature termination of pregnancy, bleeding and intrauterine infection are less common.
Prenatal diagnosis is a set of methods and procedures, the passage of which allows you to identify fetal pathologies even in the womb. Medicine has stepped so far forward that now with a high degree of probability it is possible to learn about genetic failures and anomalies in the development of an unborn child long before it is born. Regardless of the results of invasive and non-invasive methods of prenatal diagnosis, the decision to continue carrying or terminating a pregnancy is made exclusively by the parents. In addition, thanks to prenatal screening, it is possible to determine the paternity and gender of the baby with absolute certainty.
Methods of prenatal diagnosis of hereditary diseases, including genetic abnormalities, are primarily indicated for pregnant women who are at risk. Some of the chromosomal pathologies can be detected early (in the period of 13-22 weeks).
Down syndrome
This chromosomal disorder occurs most frequently, with an average of one in 800 newborns. Distinctive feature people born with Down syndrome is the presence of chromosome 47 - a healthy person has 46 of them, that is, 23 pairs. Children with this congenital disease look different. In addition, special babies are often diagnosed with strabismus, hearing problems, severe malfunctions in the cardiovascular system, gastrointestinal tract, and mental underdevelopment.
Existing methods of prenatal diagnosis of human hereditary diseases make it possible to determine violations according to certain parameters. In particular, the following indicators indicate a high probability of pathology:
- enlarged collar zone;
- the absence of a nasal bone (however, and if present, if its size is below normal).
An indirect sign of Down's syndrome may be violations of the already formed sections of the intestine. Experienced specialists will also notice chromosomal pathological changes according to the results of a pregnant woman's blood test. But in order to make a final diagnosis and decide on the future fate of the fetus, the conclusions of direct methods of prenatal diagnosis are necessary.
Shereshevsky-Turner syndromes and X-trisomy
A less common genetic disorder that occurs when one of the X chromosomes is missing or damaged. This also explains why Shereshevsky-Turner syndrome occurs only in females. If during pregnancy the methods of prenatal diagnosis of hereditary diseases were not applied, then after the birth of the child, the parents will immediately notice the symptoms of the disease. In such children, growth retardation, underweight are noted. Girls with Shereshevsky-Turner syndrome will be visually distinguished from their peers by a short and thickened neck, an abnormal shape of the auricles and hearing loss. AT adolescence there is a delay in puberty, the mammary glands do not fully develop, menstruation does not occur. Intellectual thinking is usually not affected, but adult women with this genetic disorder cannot have children.
X-trisomy syndrome, like the previous congenital pathology, occurs only in females. Mental retardation, sexual immaturity, infertility are the main symptoms of the disease. The cause of the disorder is the presence of three X chromosomes in the genotype.
Hemophilia
This disease, associated with a violation of the functions of blood coagulation, is hereditary. Mostly men are ill with it, but at the same time, the carrier of the hemophilia gene is the mother, who transmits the disease from her father to her sons. Incest (relations of parents) increases the risk of developing pathology, as a result of which a mutation of the X chromosome occurs in one of the genes.
Klinefelter syndrome
This pathology occurs if an additional female chromosome appears in the genotype. Only men suffer from it. Patients experience physical and speech development, the physique is disproportionate, the genitals do not mature. In boys with Klinefelter's syndrome, the mammary glands are enlarged according to the female type, there is a meager growth of body hair. A genetic disease is often accompanied by epilepsy, schizophrenia, and diabetes mellitus. In most cases, people with Klinefelter's syndrome have mild mental retardation. In adulthood, patients find it difficult to establish contacts with other people, they are prone to alcoholism.
Other intrauterine pathologies
It is impossible to overestimate the importance of methods of prenatal diagnosis of hereditary diseases.
In addition to the indicated chromosomal abnormalities, other failures in the development of the fetus can be determined in utero:
- Anomalies in the formation of the brain and cranial bones. The most common example is hydrocephalus, which occurs against the background of an imbalance in the production and absorption of cerebrospinal fluid. Hypoxia can provoke hydrocephalus in the later stages, infectious diseases, smoking mother.
- Heart defects. The chances of successful treatment of intrauterine pathology increase if surgery is performed in the first days, and in severe cases, in the first hours after birth.
- Absence or underdevelopment of internal organs. An anomaly can be detected using indirect methods of prenatal diagnosis (ultrasound screening) for a period of 13-17 weeks. Most often, the absence of a second kidney or the presence of a third organ is detected. Pathology may be accompanied by growth retardation and general development of the fetus, deficiency in the formation of amniotic fluid, placental changes.
- Misformed limbs.
Learn more about research
As already noted, prenatal diagnostic methods are conventionally divided into invasive and non-invasive (direct and indirect).
The first group includes procedures that do not pose any danger to both the mother and her unborn baby. Non-invasive methods of prenatal diagnosis do not imply the implementation of surgical procedures that could cause injury to the fetus. Such studies are shown to all expectant mothers, regardless of age, chronic or hereditary diseases in history. Non-invasive methods of prenatal diagnosis are usually a complex of two mandatory procedures - ultrasound and analysis of the blood serum of a pregnant woman.
How many times pregnant women need to undergo ultrasound
Ultrasound screening belongs to the category of planned and mandatory procedures. It is not advisable to refuse this examination: the procedure is harmless, does not bring any discomfort, and most importantly, it helps to determine how well the baby is developing in the womb, and whether there is even the slightest chance of any deviations.
- In the first trimester, thanks to screening, it is possible to determine the gestational age as accurately as possible, exclude ectopic development of the fetal egg and the presence of cystic drift, find out about the number of embryos and make sure that they are viable. The first ultrasound diagnosis is carried out at 6-7 weeks. If a woman had miscarriages before this pregnancy, it is established whether there is a threat of spontaneous interruption.
- In the second trimester (approximately at 11-13 weeks), parents can get an answer to the question about the gender of the expected baby. Of course, in a three-month gestation period, it is impossible to say with absolute certainty whether a couple will have a boy or a girl. More precisely, the doctor will be able to say about the sex of the child in about a couple of months. A planned ultrasound of the second trimester is mandatory, as it allows you to timely detect possible malformations of internal organs and exclude chromosomal pathologies.
- The third ultrasound screening is carried out for a period of 22-26 weeks. The study reveals the norms or delays in fetal development, diagnoses the level of amniotic fluid.
Screening of blood serum for the presence of chromosomal pathologies
The study is carried out on the basis of blood samples taken from the vein of the expectant mother. As a rule, screening is carried out in the period from 16 to 19 weeks, in rare cases it is allowed to do an analysis at a later date. Serum analysis is called a triple test by physicians, as it provides information on three substances on which, in fact, a favorable course of pregnancy depends (alpha-fetoprotein, human chorionic gonadotropin and unconjugated estriol).
This method of prenatal diagnosis helps to establish fetal anomalies and chromosomal abnormalities with an accuracy of up to 90%. The second most common pathologies, after Down syndrome, are Edwards and Patau syndromes. Newborns with such deviations in nine out of ten cases do not live even the first year.
It is impossible to identify intrauterine anomalies in the early stages, therefore, planned diagnostics cannot be neglected. According to the results of an ultrasound examination at 11-13 weeks, the doctor may suspect abnormalities and refer the woman for a clarifying screening of blood serum.
Invasive methods of prenatal diagnosis
Research procedures involving instrumental penetration into the womb are prescribed to pregnant women if routine screenings have shown poor results. During an invasive examination, biomaterial is taken (samples of cells and tissues of the fetus, placenta, amniotic fluid, fetal membranes) for the purpose of its detailed study in the laboratory.
Amniocentesis
Relatively safe procedure, since the risk of abortion during its implementation does not exceed 1%. Amniocentesis is the sampling of amniotic fluid to study its chemical composition through a puncture. In conclusion, experts determine the degree of maturity of the fetus, determine the likelihood of hypoxia, the presence of an Rh conflict between the fetus and the woman. Most often, the study is carried out at 15-16 weeks.
Chorionic biopsy
The optimal period for this method of prenatal diagnosis is the first trimester. Later than 12 weeks, the chorion biopsy is not carried out. The essence of the method of prenatal diagnosis: using a catheter inserted into the cervix, specialists collect samples of chorionic tissues. Manipulation is performed under local anesthesia. The resulting material is sent for chromosomal studies that can confirm or exclude the fact of a genetic anomaly. During a biopsy, the probability of abortion is low - no more than 1%.
This type of invasive diagnostics has side effects. Most often, after the procedure, women complain of pain in the lower abdomen, light bleeding. Unpleasant sensations and discomfort do not indicate a deviation, do not affect the development of the unborn baby and pass in a couple of days.
An indication for a chorionic biopsy may be a hereditary disease such as cystic fibrosis. With this pathology, the production of a protein responsible for the transport of fats is disrupted, as a result of which the patient's digestive processes are disturbed, immunity is reduced. This disease is not treated, but timely diagnosis allows the child to provide all the necessary conditions to combat the disease.
Fetal tissue analysis
Listing prenatal diagnostic methods that will allow timely recognition of intrauterine pathology is not so simple. But still, there is one procedure that occupies a special place among invasive studies - a biopsy of fetal tissues. It is usually carried out in the second trimester of pregnancy. The process itself is carried out under the supervision of several specialists and involves the use of ultrasonic equipment. The purpose of this diagnosis is to take samples of the skin of the fetus. The results of the analysis will allow to exclude or confirm hereditary diseases of the epidermis.
No ultrasound can establish the exact likelihood of developing skin pathologies such as albinism, ichthyosis or hyperkeratosis. Prenatal diagnostic methods that involve penetration into the womb open up more options for doctors.
One of the indications for a biopsy of fetal tissues is the suspicion of ichthyosis. This genetic disorder is extremely rare characteristic feature is the deformation of epithelial tissues and their acquisition of a look similar to fish scales. The skin becomes horny, rough, flaky, becomes dry, the nail plates are deformed. This disease is extremely dangerous for the fetus - most cases end in miscarriage or stillbirth. Unfortunately, children born with such a defect are doomed - only a few of them live up to the first month. Having detected the disease in time, parents will be able to decide to terminate the pregnancy due to the non-viability of the fetus.
Cordocentesis
Speaking briefly about the methods of prenatal diagnosis, one cannot but mention the most unsafe procedure for the mother and fetus. Cordocentesis is a serious invasive intervention, the purpose of which is to collect cord blood and its further laboratory analysis. The second trimester is considered the optimal period for the procedure, mainly 22-25 weeks.
Doctors decide to resort to this invasive method of prenatal diagnosis in the case when other manipulations are unacceptable due to the long gestation period. In addition, the study must be performed according to strict indications:
- the age of the pregnant woman exceeds 35 years;
- unsatisfactory indicators of a biochemical blood test;
- high probability of Rhesus conflict;
- hereditary pathologies in one of the parents.
Cordocentesis is not performed if the expectant mother has a high risk of miscarriage or a benign tumor of the uterus. The procedure is unacceptable during the period of recurrence of infectious and chronic diseases.
The informativeness of cordocentesis allows using this method to detect chromosomal diseases. In addition to genetic abnormalities, it is used to diagnose Ducheshen's dystrophy, cystic fibrosis, fetal hemolytic disease, and several thousand other diseases.
Fetoscopy
Another modern method of prenatal diagnosis, which involves the introduction of a probe into the uterus for visual examination of the fetus. The examination is carried out at 18-19 weeks of pregnancy. Fetoscopy is used in rare cases and for the strictest medical indications, since the risk of miscarriage due to penetration of the device can be as high as 10%.
Other invasive diagnostics include placentobiopsy (taking samples of the placenta and their laboratory examination) and fetal urine analysis.
Indications for invasive procedures
As already mentioned, not all methods of prenatal diagnosis are required. Not every expectant mother has to undergo a comprehensive examination with penetration into the womb. Any of the invasive studies is associated with a risk to the fetus, and therefore, diagnostics are prescribed for medical reasons, which include:
- the mature age of one or both parents (mother over 35, and father 45 years old);
- conclusions of indirect diagnostic methods indicating the development of defects;
- the birth of a child with genetic diseases in the family;
- dangerous infectious diseases transferred to a pregnant woman (chicken pox, rubella, toxoplasmosis, herpes, etc.);
- mother carrying a hemophilic gene;
- deviation from the norm of biochemical parameters;
- receiving a large dose of radiation from one or both parents before pregnancy.
The presence in the risk group of hereditary genetic diseases does not mean at all that the fetus will certainly develop with disorders. If, for example, the family already has a child with a chromosomal pathology, the likelihood that the second baby will be born sick is negligible. But still, the predominant number of couples want to play it safe and make sure that the future heir does not have any vices.
Prenatal screening results differ high level reliability and credibility. Research is being conducted in order to refute the fears of future parents about pathology or to prepare them for the birth of a special baby.
Doctors should give recommendations on the need for invasive diagnostics and prescribe a study: an obstetrician-gynecologist, a specialist in genetics, a neonatologist and a pediatric surgeon. In this case, the final decision depends on the mother. Most often, an additional examination is offered to parents in adulthood. But there are exceptions to any rule: children with Down syndrome are often born to young women.
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