LECTURE 2 METHODS FOR ASSESSING FETAL CONDITION

Careful collection of the somatic and obstetric-gynecological anamnesis of a pregnant woman is the first and predetermining stage in assessing the state of the intrauterine fetus and predicting the features of its further development. Extragenital pathology in a woman is a risk factor for the development of placental insufficiency, fetal growth retardation syndrome, the birth of a premature baby, and even fetal malformations (diabetes mellitus). The presence of spontaneous abortion, especially in the first trimester, may indicate the influence of a hereditary factor. The birth of a child with a developmental defect from previous pregnancies requires a thorough assessment of the condition of the fetus with this, starting from the first trimester.

Clinical methods of prenatal diagnosis are simple, but their diagnostic accuracy is insufficient. Almost 60% of pregnant women do not have FGRP detected by clinical methods, almost all pregnant women with intrauterine infection of the fetus and malformations of its development cannot be detected by clinical methods. On the other hand, only 30% of pregnant women sent to the hospital with a diagnosis of "placental insufficiency" cannot be confirmed. One of the simplest clinical methods is planimetric assessment (determination of the height of the uterine fundus and abdominal circumference and their assessment). But the height of the uterine fundus can be influenced by various factors (number of fetuses, type of presentation, placenta previa, etc.). It may also be useful to auscultate the fetus and determine the motor activity of the fetus (the number of its movements for a certain period of time, determined by the pregnant woman herself). In general, they are indicative and do not replace screening ultrasound and biochemical studies.

CONCEPT OF PRENATAL DIAGNOSTICS. ORGANIZATION OF THE PRENATAL SERVICE

DIAGNOSTICS

The main tasks of obstetrics are to create optimal conditions for a woman to exercise the function of motherhood, preserve her health and ensure the birth of healthy offspring. The decrease in the birth rate and the increase in mortality observed in Russia is largely due to socio-economic reasons (unstable economic situation, tense psychological situation, decline in the standard and quality of life) and cannot be solved only by the efforts of healthcare institutions. In these conditions, the task of paramount importance is to reduce perinatal morbidity and mortality. Against the background of low fertility, perinatal mortality, although it tends to decrease over the past 10 years, remains quite high (13.18% in 2001). The timely diagnosis of fetal malformations and chromosomal abnormalities acquires a special meaning, which makes it possible to decide on the advisability of prolonging pregnancy until the fetus reaches viability. Malformations of varying severity and different systems are observed in 2-3% of live births. In addition, in another 2-3%, malformations appear before the age of 5 years. The so-called "minor" violations of embryonic development, often defined as stigmas, are observed in 15% of newborns, and 3-15% of them also have more severe structural, morphological or functional disorders. In 40-60% of newborns with developmental defects, the cause of the anomaly is unknown.

Human chromosomal diseases, most of which are represented by a violation of the number of chromosomes (chromosomal aberrations) - aneuploidies, are not only a medical problem, since they are often accompanied by the presence of malformations, but also have a significant social aspect. The incidence of aneuploidy is 7 per 1000 newborns. Up to 80% of observations of chromosome abnormalities are the result of newly emerging mutations (mutations de novo). In this regard, the generally accepted approach in prenatal diagnosis of malformations and chromosomal abnormalities is the formation of groups of pregnant women with a "high" risk of having children with chromosomal pathology using a complex

clear schemes and various screening methods, primarily ultrasound and biochemical.

In the past 40 years, thanks to the success of reproductive biology and the introduction of new technologies into clinical practice, there has been significant progress in the accumulation and use of knowledge about the laws of development of the embryo and fetus, which made it possible to formulate the concept of prenatal diagnosis.

Prenatal diagnostics, according to the recommendations of the WHO and the European Association of Prenatal Medicine, can be defined as “the totality of all methods for diagnosing the condition of the fetus, which is aimed at the prenatal detection of congenital defects, which are any abnormalities in morphological, structural, functional or molecular development diagnosed at birth (although they may manifest later), external or internal, hereditary or sporadic, single or multiple. " The main tasks of prenatal diagnosis, according to the recommendations of the Royal College of Medicine in London (1989), are:

Providing a married couple with a high risk of having a child with developmental defects or chromosomal abnormalities, the maximum possible information about the risk of having a sick child;

Providing psychological support to a married couple;

Providing a married couple, on the basis of the most complete information about the state of the fetus, the opportunity to choose the optimal decision on prolongation or termination of pregnancy;

The choice of the optimal tactics of pregnancy management, method of delivery and treatment of a newborn with defects compatible with life.

According to the Order of the Ministry of Health of the Russian Federation? 457 of 28.12.2000 "On the improvement of prenatal diagnostics in the prevention of hereditary and congenital diseases in children" the basis for prenatal (antenatal) examination is artificial intrauterine selection (elimination) of genetically defective fetuses. Methods are used to accurately diagnose fetal abnormalities of both chromosomal and gene origin, as well as other malformations.

In order to increase the efficiency of prenatal diagnosis of severe, non-treatable hereditary and congenital diseases, the examination of pregnant women is carried out according to a certain scheme. The main methods of prenatal diagnostics all over the world are recognized as ultrasound, biochemical (serum) screening and invasive diagnostic methods with subsequent karyotyping of the fetus.

The generally accepted risk factors for the development of congenital and hereditary fetal pathology are the age of the pregnant woman over 35 years old, the presence of a hereditary disease in the family, the birth of a child with developmental defects or chromosomal abnormalities, chromosomal aberrations in one of the spouses, consanguineous marriage.

When forming risk groups of pregnant women from the point of view of the birth of children with congenital and hereditary pathology, it is necessary to take into account not only the factors that could lead to the development of pathology in children, but also those that cause complications in the course of pregnancy. Already at the initial visit of the patient, it is important to assess social, environmental factors, as well as the characteristics of the anamnesis (family, gynecological, obstetric) and the course of this pregnancy. The most common risk factor and, therefore, an indication for a thorough examination of the patient is the threat of early termination of pregnancy (3-6 weeks). In women with miscarriage, structural abnormalities of the karyotype occur 10 times more often than in the population, and account for about 2.5%. The second most common symptom is unfavorable exogenous factors (bad habits, taking teratogenic drugs, occupational hazards, living in areas of environmental disasters). One of the important indications for the examination of pregnant women is a history of infertility. In addition, a teratogenic effect on the fetus has been proven with the formation of congenital malformations of infections such as cytomegalovirus, herpes simplex virus, rubella, toxoplasmosis.

The introduction of echography into practical obstetrics in the middle of the XX century. revolutionized the development of prenatal diagnostics.

In the overwhelming majority of fetuses with large chromosomal defects, either external or internal malformations are noted, which can be diagnosed with careful

nominal ultrasound examination. It should be noted that today the identification of markers of fetal chromosomal pathology by echography is one of the methods of forming a group of pregnant women for invasive procedures and subsequent karyotyping. In the first trimester, the most significant echographic signs of fetal pathology are an increase in the thickness of the collar space, a discrepancy between the coccyx-parietal size of the embryo and the gestational age, cystic hygroma of the neck, omphalocele, congenital heart defects, megacystics. Collar space- the area between the inner surface of the fetal skin and the outer surface of the soft tissues that cover the cervical spine. The assessment of the thickness of the collar space (TVP) is carried out at 10-14 weeks of pregnancy with numerical values of the coccygeal-parietal size of the fetus from 45 to 84 mm. The frequency of chromosomal abnormalities is directly proportional to the size of the TVP. According to P. Pandya et al. (1995), with TBP 3 mm chromosomal defects were found in 7% of fetuses, with 4 mm - in 27%, with 5 mm - in 53%, with 6 mm - in 49%, with 7 mm - in 83%, with 8 mm - for 70%, with 9 mm and more - 100%. In addition, it should be noted that the incidence of congenital malformations of the fetus increases with an increase in the collar space. In a study by A. Souka et al. (1997) noted that with a collar space width of up to 3.4 mm, congenital malformations were observed in 2.4% of fetuses, from 3.5 to 4.4 mm - in 7.1%, from 4.5 to 5, 4 mm - in 12.3%, and with 6.5 mm and more - in 35.6% of cases. The presented data can be used in the course of prenatal counseling and to determine the tactics of dynamic echographic observation in cases of detection of an enlarged collar space in fetuses with a normal karyotype. Currently in Russia by order of the Ministry of Health? 457 of 28.12.2000, it was established that determining the thickness of the collar space should be mandatory when conducting the first screening ultrasound examination at 10-14 weeks of pregnancy. The discrepancy between the coccygeal-parietal size is defined as a marker of pregnancy pathology with deviations of ± 2 weeks. In the presence of fetal cystic hygroma, the average detection of fetal chromosomal abnormalities is 68%, with Turner syndrome dominant. If the fetus has an omphalocele after 10 weeks of pregnancy, especially if it restrains only intestinal loops, karyotyping should be performed.

The range of detectable markers of chromosomal pathology in the second trimester is much larger and includes changes in various organs and systems. For example, when examining the brain, ventriculomegaly, holoproencephaly, microcephaly, vascular plexus cysts, anomalies of the posterior cranial fossa, and abnormal shapes of the skull ("strawberry", "lemon") can be detected. In addition, the most significant markers include congenital heart defects, hyperechoic intestines, duodenal atresia, facial pathology, enlargement of the calyx-pelvic system of the fetus, other renal anomalies, ovarian cysts in the fetus, imbalance in the length of tubular bones, anomalies of the hands and feet, umbilical cord pathology, non-immune dropsy of the fetus, polyhydramnios and oligohydramnios, symmetrical form of fetal growth retardation syndrome. To date, the data obtained during ultrasound examination are, in many cases, predetermining the choice of further examination methods (primarily invasive), and, consequently, the tactics of pregnancy management.

When choosing a rational screening program for pregnant women, it should be remembered that the accuracy of prenatal diagnosis increases with the use of multiple diagnostic tests and a careful assessment of several risk factors.

Indications for examination using invasive methods in the first trimester differ little from those in the second trimester of pregnancy. According to the traditional principles of forming a risk group for pregnant women who are threatened by birth of children with congenital and hereditary pathology, invasive studies should be offered:

Families in which one of the spouses is a carrier of a chromosomal rearrangement or both spouses are carriers of a gene mutation;

Pregnant women who have ultrasound markers of chromosomal pathology (for example, expansion of the collar space);

Pregnant women who have deviations of serum blood markers during screening biochemical studies;

Consanguineous marriage.

There are several classifications of invasive research methods during pregnancy.

1. By the nature of the access (transcervical, tranabdominal).

2. By the technique of obtaining the material (by aspiration, by biopsy).

3. By the nature of the control over the procedure (under ultrasound control, under the control of endoscopic devices).

4. By the nature of the material obtained (chorionic villi, amniotic fluid, blood from the umbilical cord).

9-12 weeks

13-14 weeks- early amniocentesis is possible, but the risk of complications when using this method is quite high. Spontaneous abortion is observed in 3.8-5.3%, and failures of culturing cells obtained from amniotic fluid are about 11-12%.

15-17 weeks

18 weeks or more

Are all invasive procedures in Russia regulated by the Order of the Ministry of Health? 45 of 28.12.2000. Invasive interventions are carried out only with the consent of the pregnant woman under the control of ultrasound examination after a mandatory gynecological examination of the woman in her satisfactory condition. Relative contraindications for invasive interventions include in the first trimester a threatening termination of pregnancy with bloody discharge, the presence of multiple myomatous nodes in the uterus, preceding laparotomy and surgery on the uterus, inflammatory diseases with an increase in body temperature. The same factors are taken into account when carrying out cordocentesis, although, according to some authors, there are no absolute contraindications for taking blood from the fetal umbilical cord vein. Possible complications of invasive procedures include spotting spotting from the genital tract and bleeding (1-4%), intrauterine infection and sepsis (0.2-0.5%). Very early chorionic villus aspiration carries the risk of

changes in limb reduction and oromandibular hypogenesis. Complications of cordocentesis include transient bradycardia (in 18.3%), bleeding from the puncture site, inflammatory complications (0.6-2.91%), and fetal loss after the procedure (2-2.5%). As can be seen from the data presented, despite the high diagnostic value, invasive procedures require a thorough assessment of both the possible risk of having a sick child and the risk of pregnancy complications with a normal fetal karyotype.

In addition to the above diagnostic tests, which have taken their definite place in the system of prenatal diagnostics, new technologies have gradually begun to be introduced into clinical medicine, which include endoscopic methods.

ULTRASONIC RESEARCH METHODS

In recent years, in obstetric practice, echography, which is highly informative, harmless to the mother and the fetus, has become increasingly widespread for assessing the development of the fetus. The basis of ultrasound diagnostics is the reverse piezoelectric effect. Ultrasonic waves, reflected from the heterogeneous structures of the emitted object, are converted into electrical impulses and reproduced on the screen of the device in proportion to the distance from the sensor to the corresponding structure, from which this signal was reflected. Currently, only real-time instruments are used. The peculiarities of using this system are the ability to quickly select the plane of the optimal section and continuous monitoring of the state of the object under study, which is especially important when examining the activity of various organs and systems of the fetus. In obstetrics, linear sensors are most widely used, since storal sensors provide only a limited field of observation. In addition, amniotic fluid is

an ideal environment for ultrasonic waves to travel, eliminating the need to scan from a small acoustic window.

In obstetrics, two main methods are most widely used: transabdominal and transvaginal scanning. For transabdominal scanning, sensors 3.5 and 5 MHz are used, for transvaginal - with a higher resolution (wave frequency 6.5 MHz and higher). The use of acoustic transducers with such a frequency during transvaginal ultrasound scanning made it possible to radically revise the aspects of ultrasound diagnosis of pregnancy and its complications, especially in the first trimester. In addition, transvaginal scanning is more comfortable for the examined woman in the early stages of pregnancy than transabdominal scanning, since it does not require filling the bladder. Among the advantages of transvaginal scanning for the diagnosis of pregnancy and associated pathology in comparison with transabdominal scanning are the following (Strizhakov A.N., Davydov A.I., 1994).

1. The use of transvaginal echography contributes to the detection of acoustic signs of pregnancy at an earlier date, which is of great importance in the choice of tactics for managing patients with a burdened obstetric and gynecological history, especially with recurrent miscarriage.

2. Transvaginal ultrasound scanning opens up the possibility of early diagnosis of pregnancy complications and their timely correction in the first trimester.

3. The use of transvaginal echography allows at an earlier date and with greater accuracy to study the acoustic aspects of embryology, to assess the development of organs and systems of the fetus, as well as to identify defects in their development; in some cases, using transvaginal ultrasound scanning, it is already possible to establish the sex of the fetus in the first trimester of pregnancy.

During transabdominal ultrasound examination, the surface of the transducer is lubricated with a sound-conducting gel for better contact with the surface of the anterior abdominal wall; during transvaginal examination, a protective rubber sheath is used to maintain asepsis.

In Russia, according to the order? 457 of the Ministry of Health of the Russian Federation, the prenatal diagnostic system includes a mandatory three-fold screening ultrasound examination of pregnant women: within 10-14 weeks (to assess the presence of markers of chromosomal pathology), at 20-24 weeks (to identify malformations and markers of chromosomal pathology), at 32-34 weeks (for the diagnosis of malformations with late manifestation and functional assessment of the state of the fetus).

With an ultrasound examination in the first trimester of pregnancy, the following is carried out:

Establishment of uterine pregnancy based on visualization of the ovum with or without an embryo in the uterine cavity;

Biometrics (average inner diameter of the ovum, coccygeal-parietal size of the embryo);

Assessment of the vital activity of the embryo (cardiac activity, physical activity);

Determination of the localization of the chorion and the exclusion of its pathology;

Study of extraembryonic formations (yolk sac, amniotic membrane and cavity, chorion);

Study of the anatomy of the embryo / fetus, identification of markers of chromosomal pathology;

Internal pharynx assessment;

Visualization of the walls of the uterus and appendages.

Additional indications for ultrasound examination in the first trimester (up to 10 weeks of pregnancy) are as follows:

The presence of uterine fibroids and tumors of the appendages;

Suspected ectopic pregnancy;

Inconsistency of the size of the uterus with the gestational age;

The presence of an intrauterine contraceptive and pregnancy;

Trauma and intoxication in a pregnant woman;

The need for a biopsy (aspiration) of the chorion;

Burdened obstetric and gynecological history.

In case of complicated pregnancy, ultrasound examination is performed at any time.

The results of numerous studies indicate the possibility of establishing pregnancy using transabdominal echography, starting from 3-4 weeks after fertilization. An echographic sign of pregnancy is the presence in the uterine cavity of the ovum in the form of a rounded echo-negative formation

Table 5. Embryo length (coccygeal-parietal size) at different times

pregnancy in the first trimester

with clear contours and an average diameter of 5-7 mm. Visualization of the embryo itself and registration of signs of its vital activity is achieved only by 4-5 weeks from the day of conception. The emergence of transvaginal echography made it possible to diagnose pregnancy 1-3 weeks earlier than with transabdominal scanning, in some cases (with dynamic observation of patients who were ovulation stimulated), it is possible to establish the presence of pregnancy in the absence of a delay in menstruation.

When examining pregnant women with a burdened obstetric and gynecological history, great importance is attached to the detection of the embryo and the assessment of its vital activity at the initial stages of development. Imaging of the embryo using transvaginal echography is possible starting from 3-4 weeks of pregnancy from the moment of conception (with transabdominal scanning it is possible not earlier than 5-6 weeks). At the indicated time, on transvaginal echograms, the embryo is defined as an oblong structure, with high echo density, 4-5 mm long, located inside the ovum. The most accurate indicator of gestational age in the first trimester is the coccygeal-parietal size of the embryo and fetus. Table 5 shows data on the size of the coccygeal-parietal size in the first trimester of pregnancy.

From the 4-5th week of pregnancy, the yolk sac is identified in the form of a ring-shaped structure, localized near the embryo

rion. The shape of the yolk sac varies from spherical to oval, its average diameter slowly increases with increasing gestational age. Usually, the yolk sac is determined up to 12 weeks from the moment of conception and reaches a diameter of 7-9 mm. Subsequently, its walls collapse and cystic degeneration occurs. The most reliable criterion for the vital activity of the embryo is the registration of its cardiac activity and motor activity. The metabolic rate of the fetus suggests the onset of cardiac pulsations, usually on the 22nd day after conception. The use of transvaginal echography makes it possible to detect heartbeats in an embryo 4-5 mm long (3.0-3.5 weeks of gestation), and the diagnosis of cardiac activity with transabdominal scanning is possible no earlier than 5-6 weeks. Heart rate at 5-6 weeks is 150-160 beats / min, at 7-8 weeks - 175-185 beats / min, at 9-10 weeks - 160-170 and at 11-12 weeks - up to 150 beats / min ... Such a change in heart rate is associated with the sequential differentiation of the anatomical structures of the fetal heart and the formation of the myocardial conduction system and the function of the vagus nerve. Extremely unfavorable ultrasound signs in the first trimester of pregnancy, indicating the presence of severe heart defects, are heart block, expansion of the collar space (with a width of more than 5 mm, the frequency of defects, according to different authors, ranges from 23 to 75%, depending on the karyotype of the fetus ), change in heart rate (bradycardia less than 100 beats / min after 9 weeks of pregnancy).

The motor activity of the fetus is detected from 7-8 weeks. There are two types of movements: movements of the limbs, trunk and combined movements. Lack of fetal cardiac activity and motor activity indicate the death of the embryo.

The high resolution of transvaginal sensors allows diagnosing non-progressive pregnancies starting from 5-7 weeks after fertilization. In such observations, an embryo with a length of 6-8 mm lacks cardiac activity and motor activity. In addition, the establishment of a non-developing pregnancy is based on the identification of an "empty" ovum (anembryony). In this case, the diameter of the ovum does not exceed 2-3 cm, while fuzzy, thickened walls are revealed due to degenerative changes.

Of particular relevance is information about the possibility of echographic visualization of internal organs and parts of the fetus in the first trimester of pregnancy. With the help of transvaginal scanning, the differentiation of parts of the embryo is possible no earlier than 9 weeks. The use of transvaginal echography makes it possible to identify the head of the embryo from 5-6 weeks, the trunk and limbs of the embryo as separate anatomical structures - from the 7th week of pregnancy. From 8-9 weeks, it is possible to differentiate the spine, stomach, liver, lungs and umbilical cord. From the 10th week, the aorta, choroid plexuses of the lateral ventricles of the brain, and individual structures of the face are determined. At the 12th week of pregnancy, the kidneys, adrenal glands, bladder, great vessels (brachiocephalic trunk, carotid arteries, pulmonary artery), as well as the main extracardial structures - ventricles, atria, interatrial and interventricular septa, atrioventricular valves) are detected. At the end of the first trimester, a detailed assessment of the intracranial anatomy of the fetus is also feasible.

In recent years, transvaginal ultrasound diagnostics of fetal anomalies has been of great importance. The most accessible of them for antenatal ultrasound diagnostics are anomalies of the anterior abdominal wall (omphalocele and gastroschisis), anencephaly, exencephaly, cervical meningomyelocele, syndactyly, polycystic kidney disease, non-immune dropsy of the fetus, tetrad of Fallot, clubfoot. Transvaginal echography is of great practical importance in assessing the state of the cervix and the lower uterine segment during pregnancy. This research method allows with a high degree of accuracy to assess the state of the uterine pharynx, diagnose its premature opening, chorionic presentation (placenta) and its partial or complete detachment.

The threat of termination of pregnancy is characterized by the presence of a local thickening of the myometrium due to its increased tone. It is important to emphasize that this echographic sign appears earlier than clinical symptoms and disappears later.

Bubble drift is detected by ultrasound examination by the presence of multiple echo complexes in the uterine cavity, reminiscent of a "snow storm". In 50% of observations, multichamber tecalutein ovarian cysts of various sizes are detected.

Some difficulties are possible with an echographic examination in order to detect an ectopic pregnancy, while transvaginal scanning has an indisputable advantage. In the process of transvaginal ultrasound examination, if an ectopic pregnancy is suspected, the condition of the uterus, fallopian tubes, ovaries, vesicouterine and rectal-uterine cavities is consistently assessed. Taking into account the extremely rare combination of uterine and ectopic pregnancies, it is important to identify the ovum in the uterine cavity. The most reliable acoustic criterion for an ectopic pregnancy is the establishment of the ectopic localization of the ovum with a living embryo. In addition, in a diverse ultrasound picture (especially in case of a disturbed tubal pregnancy) of an ectopic pregnancy, it is recommended to take into account an increase in the uterus in the absence of organic changes or uterine pregnancy, a thickening of the median M-echo, the identification of an inhomogeneous structure and free fluid in the area of the uterine appendages (isolated from the ovary) in the recesses of the small pelvis. The possibilities of ultrasound diagnostics should be considered in a complex of other diagnostic measures.

An indisputable advantage is the ultrasound examination in pregnant women with uterine myoma and tumor-like formations of the uterine appendages, which makes it possible to accurately determine the anatomical and topographic relationships between the nodes and the fetal-placental system, the structure of the neoplasm of the appendages, its localization and size. Transvaginal scanning provides much more valuable data in the early stages of pregnancy. The results of the study are important for the management of pregnancy and childbirth.

Ultrasound diagnosis of multiple pregnancies is based on visualization of several fetuses or embryos in the uterine cavity. The experience of the conducted studies shows that there is a discrepancy between the number of twins identified in early pregnancy and the number of twins born. This discrepancy is due to the anembryony of one of the fetal eggs or the subsequent death of one of the embryos, therefore, in pregnant women with multiple pregnancies, it is necessary to conduct ultrasound in dynamics for early detection of fetal developmental disorders.

It should be noted that today the identification of markers of fetal chromosomal pathology by echography is one of the methods of forming a group of pregnant women for invasive procedures and subsequent karyotyping. In the first trimester, the most significant echographic signs of fetal pathology are an increase in the thickness of the collar space, a discrepancy between the coccyx-parietal size of the embryo and the gestational age, cystic hygroma of the neck, omphalocele, congenital heart defects, megacystics. Collar space- the area between the inner surface of the fetal skin and the outer surface of the soft tissues that cover the cervical spine. The assessment of the thickness of the collar space (TVP) is carried out at 10-14 weeks of pregnancy with numerical values of the coccygeal-parietal size of the fetus from 45 to 84 mm. The frequency of chromosomal abnormalities is directly proportional to the size of the TVP. According to P. Pandya et al. (1995), with TBP 3 mm chromosomal defects were found in 7% of fetuses, with 4 mm - in 27%, with 5 mm - in 53%, with 6 mm - in 49%, with 7 mm - in 83%, with 8 mm - for 70%, with 9 mm and more - 100%. In addition, it should be noted that the incidence of congenital malformations of the fetus increases with an increase in the collar space. In a study by A. Souka et al. (1997) noted that with a collar space width of up to 3.4 mm, congenital malformations were observed in 2.4% of fetuses, from 3.5 to 4.4 mm - in 7.1%, from 4.5 to 5, 4 mm - in 12.3%, and with 6.5 mm and more - in 35.6% of cases. The presented data can be used in the course of prenatal counseling and to determine the tactics of dynamic echographic observation in cases of detection of an enlarged collar space in fetuses with a normal karyotype. Currently, in Russia, by order of the Ministry of Health dated December 28, 2000, it was established that determining the thickness of the collar space should be mandatory when conducting the first screening ultrasound examination at 10-14 weeks of pregnancy. The discrepancy between the coccygeal-parietal size is defined as a marker of pregnancy pathology with deviations of ± 2 weeks. In the presence of fetal cystic hygroma, the average detection of fetal chromosomal abnormalities is 68%, with Turner syndrome dominant. If the fetus has omphalocele after 10 weeks of pregnancy, especially if it contains only intestinal loops, karyotyping should be performed.

During the second screening ultrasound examination during pregnancy, you must:

Determine the number of fruits, their position and presentation;

Measure the main fetometric parameters and assess their compliance with the gestational age;

Study the basic ultrasound anatomy of the fetus;

Assess the amount of amniotic fluid, localization, thickness and structure of the placenta;

Carry out a study of the anatomical features of the body, cervix and appendages.

The minimum required volume of fetometry includes the determination of the biparietal size of the head, the length of the femur and the average diameter (circumference) of the abdomen.

Screening ultrasound assessment of fetal anatomy usually follows the following scheme:

Visualization of cross-sections of the head at different levels;

Study of facial structures;

Assessment of the fetal spine with longitudinal and transverse scanning;

Visualization of the cross-section of the chest with the study of a four-chamber section of the heart and lungs of the fetus;

Longitudinal section of the fetal body to assess the diaphragm;

Examination of the anterior abdominal wall;

Visualization of the stomach, liver, spleen and intestines;

Assessment of the kidneys and bladder;

Examination of fetal limb bones.

When studying the fetus in the II and III trimesters of pregnancy, the main attention is paid to measuring the biparietal size of the head (BPD), the average diameters of the chest and abdomen (DH and DB) and abdominal circumference (OB), as well as the length of the thigh (DB) (Fig. 7- nine). The biparietal size of the head should be determined only with the best visualization of the median M-structure from the outer surface of the upper contour to the inner surface of the lower contour of the head.

When scanning the fetal head, the visual hillocks, cerebellar tentorium, cerebellar hemispheres, brain stem and legs, and ventricles are clearly visualized. The average diameter of the chest is measured at the level of the cusp valves of the fetal heart, the average diameter of the abdomen is measured at the umbilical vein origin. To determine

By changing the length of the femur, the sensor should be shifted to the pelvic end of the fetus and, by changing the angle and plane of scanning, to achieve the best image of the longitudinal section of the femur. The greatest distance between the proximal and distal ends should be measured. An image of the extremities with ultrasound scanning can be obtained from the 7th week of pregnancy, i.e. from the moment of laying in the diaphysis of the primary point of ossification. It is possible to accurately measure the length of the thigh from 12-13 weeks of gestation, when the ossification process covers the entire diaphysis.

It was found that with the development of the fetus, all of the above indicators progressively increase, however, by the end of pregnancy, the rate of their growth gradually decreases. Thus, the rate of increase in bipolar disorder decreases from 4 mm / week at 14-15 weeks of gestation to 1.3 mm / week by the end of the pregnancy, DB - from 4.8 mm / week to 1.7 mm / week. Table 6 shows the changes in fetometry data in the II and III trimesters of pregnancy, taking into account individual fluctuations.

Determination of the fetal body weight during ultrasound examination is carried out according to formulas based on the measurement of the abdominal circumference and BPD. The most acceptable for clinical practice are the formulas of S. Campbell and A. Thoms (1977), S. Warsof et al. (1977) and M. Shepard et al. (1982).

It is also important to calculate the estimated length of the fetus by measuring the length of the thigh to determine the degree of maturity of the fetus. It was established (Strizhakov A.N. et al., 1989) that at the end of the internal

Rice. 7. Measurement of the biparietal diameter of the fetal head

Rice. eight. Measuring the abdominal circumference of the fetus

Rice. nine. Fetal hip measurement

During the prenatal period of development, ultrasound examination can visualize the secondary ossification point in the distal epiphysis of the thigh (Beklar's nucleus). With sufficient maturity of the fetus, the total length of its thigh is 7 cm or more, the size of the Beklar nucleus ranges from 5-7 mm. The relationship between fetal length and femur length is expressed by the following equation:

Table 6. The main parameters of fetometry at various times

pregnancy *

Note.* Biparietal head size (BPD), average chest and abdominal diameters are given according to L.S. Persianinov and V.N. Demidov (1982), thigh length - according to A.N. Strizhakov and M.V. Medvedev (1984).

D = 0.508B - 0.56B + 28.68,

where: D is the length of the fruit, cm; B - fetal thigh length, see

Using this equation makes it possible to predict the length of the newborn with an accuracy of ± 1 cm in 71.4% and ± 2 cm in 88.6% of observations.

Ultrasound examination is one of the most objective methods for diagnosing intrauterine growth retardation of the fetus. Ultrasound diagnosis of this pathology is based on

on the comparison of fetometry data obtained in the study with standard indicators for a given gestational age. Distinguish between symmetric and asymmetric forms of fetal growth retardation, which are characterized by different ratios of the main fetometric parameters, timing of occurrence and etiological factors. With a symmetrical shape, all fetometric indicators (biparietal head size, average chest and abdominal diameters, thigh length) are below the normal values of individual fluctuations for the corresponding gestational age. The asymmetrical shape is characterized by a predominant decrease in the size of the abdomen and chest. Biparietal head size and fetal femur length remain within the normal range. Consequently, it is these two indicators that can serve as criteria for distinguishing the forms of intrauterine growth retardation of the fetus. With ultrasound fetometry, it is possible to determine the severity of intrauterine fetal growth retardation. With I degree, there is a lag in fetometry parameters by 2 weeks, with II degree - by 3-4 weeks, with III degree, there is a decrease in size by more than 4 weeks. An important indicator for evaluating the effectiveness of the therapy is the rate of increase in fetometric indicators. The termination of the growth of parameters, as well as the presence of a symmetrical form of fetal growth retardation of the III degree, indicates a significant violation of its vital activity and serves as an indication for early delivery. The high frequency of the combination of congenital malformations with a symmetrical form of intrauterine growth retardation requires a thorough examination of the internal organs of the fetus.

Currently, echography allows you to examine most of the internal organs of the fetus: heart, liver, stomach, kidneys and adrenal glands, bladder, which makes it possible to terminate pregnancy early in case of severe developmental anomalies.

The most easily recognized congenital lesions of the central nervous system. So, anencephaly is characterized by the absence of head contours, only the base of the skull with large "bulging" orbits is revealed. Diagnosis of hydrocephalus is based on the detection of fluid in the ventricles of the brain (internal hydrocephalus) and under the dura mater (external hydrocephalus). A large amount of fluid is accompanied by a significant increase in biparietal

the size of the fetal head. In such cases, the ratio between the circumference of the head and the circumference of the abdomen (chest circumference) increases sharply.

The fetal spine is visualized as separate echo-positive formations corresponding to the vertebral bodies. It is possible to determine all parts of the spine, including the sacrum and coccyx. In this regard, diagnostics spina bifida usually not difficult. The exception is cases with small sizes of hernial protrusion.

Examination of the fetal heart must be carried out in 6 sections to specifically exclude congenital damage to the cardiovascular system: four-chamber section, four-chamber section with the base of the aorta, section along the long axis of the left ventricle, section along the long axis of the right ventricle through the vena cava, section through the aortic arch and section through the pulmonary trunk. These examinations require special training and sufficient experience, therefore, in wide clinical practice, a four-chambered section of the fetal heart, obtained by strictly transverse scanning of the chest at the level of the leaflet valves, can be successfully used. The left and right ventricles, left and right atrium, interventricular and interatrial septa, mitral and tricuspid valve cusps, as well as the foramen ovale valve are clearly visualized. To detect cardiomegaly, it is necessary to use the cardiothoracic index, which is normally 0.50-0.54.

The use of the M-method makes it possible to assess the features of the pumping and contractile functions of the myocardium in the antenatal period by determining the size of the ventricles of the heart in different phases of the cardiac cycle (Fig. 10). It should be noted that from the end of the second trimester and throughout the third trimester of pregnancy, there is a functional predominance of the size of the right ventricle over the left, which is associated with the peculiarities of intrauterine circulation. Indicators of the central hemodynamics of the fetus are important for determining its compensatory capabilities in the complicated course of pregnancy.

Currently, it is possible to diagnose most of the congenital heart defects. Echocardiographic examination reveals a significant increase in the right heart of the fetus due to the right atrium. The right ventricle consists of two

parts: the actual ventricle and the atrialized space, echographically defined as a component of the right atrium. Defects of intracardiac septa are established by the absence of their integrity in several echographic sections of the heart.

Ultrasound recording of fetal respiratory movements helps to determine the maturity of the respiratory muscles and the nervous system that regulates them. From 32-33 weeks, fetal respiratory movements become regular and occur with a frequency of 30-70 movements per minute. Respiratory movements are the simultaneous movements of the chest and abdominal walls. With apnea, the chest is enlarged. When breathing occurs, the anterior chest wall moves inward, and the anterior abdominal wall moves outward. Then they return to their original state. In complicated pregnancy, the number of respiratory movements increases to 100-150 per 1 min or decreases to 10-15 per 1 min, while individual convulsive movements are noted, which is a sign of chronic intrauterine fetal hypoxia.

With the use of antenatal ultrasound diagnostics, it is possible to establish congenital malformations of the gastrointestinal tract and timely, before complications develop, transfer newborns to specialized surgical departments for surgical treatment. Normally, the fetus is visualized

Rice. ten. M-method for recording fetal cardiac activity

in the upper abdomen of a comparatively large ovoid shape, only a fluid formation that corresponds to the stomach. When determining the size of the stomach, it was found that they are subject to individual fluctuations. Congenital malformations of the intestine are detected by ultrasound, usually by the presence of voluminous fluid, often multiple, formations in the abdominal cavity of the fetus. The diagnosis of congenital hernias, visualized in the form of a volumetric formation of a round shape with hernial contents adjacent directly to the abdominal wall of the fetus, does not present significant difficulties either. The use of ultrasound can clearly identify the kidneys, adrenal glands and bladder. The bladder, depending on the filling, has an ovoid or pear-shaped shape. It was found that with a normal pregnancy, the production of urine in the fetus is 20-25 ml / h. With gestosis and intrauterine growth retardation of the fetus, urine production decreases, which is a sign of a violation of the functional state of the fetus. It is possible to diagnose renal anomalies such as agenesis, hydronephrosis and polycystic disease.

Antenatal sex determination of the fetus is important both for the diagnosis and for the treatment of pathologically proceeding pregnancy (mainly when there is a suspicion of genetic and chromosomal abnormalities in the fetus). Intrauterine determination of the sex of the fetus using transabdominal echography is possible no earlier than 20 weeks of pregnancy. The use of transvaginal ultrasound scanning makes it possible to identify secondary sexual characteristics of the sex of the fetus starting from 13-16 weeks of pregnancy. Diagnosis of the male sex is based on visualization of the penis in the form of a simple linear echo and scrotum, detected by transverse scanning of the trunk and lower extremities of the fetus. The female fetus is characterized by the appearance of 2 or 4 parallel lines, reflecting the labia majora and minora.

The question of diagnosing free fluid in the fetal cavities deserves special attention, since in most cases its presence indicates severe congenital malformations or a pronounced edematous form of hemolytic disease. Severe ascites is characterized by the presence of an echo-negative space that occupies a significant part of the abdominal cavity

fetus. With ultrasound examination, hydrothorax, especially with a large amount of fluid, is manifested by the presence of echo-negative spaces that occupy the entire chest. Fetal lungs are not visualized. The hydropericardium is better detected in the form of an echo-negative cavity between the pericardium and the myocardium when using the M-method. It should be noted that the pathological hydropericardium is considered when the thickness of the strip exceeds 2 mm. If free fluid is found in the fetal cavities, it is necessary to examine the heart in detail, since there is a high frequency of the combination of congenital heart defects with the presence of ascites, hydropericardium and hydrothorax.

Intrauterine fetal death during ultrasound examination is characterized by the absence of cardiac activity, with enlarged chambers of the heart, deformation of the head and signs of autolysis of the internal organs of the fetus, as well as changes in the midline structures of the brain.

The use of ultrasound in placentography allows you to accurately establish the localization of the placenta, its thickness and structure. With real-time scanning, a clear image of the placenta is usually obtained from 7-8 weeks of pregnancy. In most cases, the placenta is visualized as an echo-positive formation of medium density, located on

several walls of the uterus, against the background of amniotic fluid, free from echoes.

The shape of the placenta can be different: flat-convex - when the placenta is located on the anterior or posterior wall of the uterus with a transition to one of the side walls; in the form of a crescent - when located on the side wall of the uterus with a transition to the front and back walls. The placenta is located more often on the front or back surface of the uterus with a transition to one of the side walls. In isolated observations, it is localized in the bottom of the uterus.

Localization of the placenta at different stages of pregnancy is unstable. It was found that the frequency of low location and placenta previa before 20 weeks of gestation is 11%. Subsequently, in most observations there is a "migration" of the placenta from the lower segment to the fundus of the uterus. The final conclusion about the location of the placenta should be made only at the end of pregnancy, by comparing it with the results of previous studies. Such attachment of the placenta is considered to be low when, during an echographic examination, the distance between its lower edge and the internal os of the cervix will be less than 7 cm.

To establish placenta previa, the study must be carried out with a well-filled bladder in order to better visualize the cervix and the area of the internal os. Placenta previa during echographic examination is characterized by the presence of placental tissue in the area of the internal os. Sometimes, with the localization of the placenta on the posterior wall of the uterus, difficulties in making a diagnosis are possible due to the significant absorption of ultrasonic waves by the presenting head of the fetus. In such cases, placenta previa can be established based on an increase in the distance between the back wall of the uterus and the fetal head by 2 cm or more. If this distance does not decrease when pressing on the fetal head with a hand from the side of the anterior abdominal wall, then this will be an additional sign confirming this diagnosis (Fig. 11). If placenta previa is detected before 20 weeks of pregnancy, ultrasound examination should be performed every 4 weeks until the end of pregnancy or until the placenta moves from the internal os of the cervix to a distance of more than 2-3 cm.

With the use of ultrasound placentography, it became possible to diagnose premature detachment of a normally located placenta in the early stages of its occurrence. This pathology is characterized by the presence of an echo-negative space between the wall of the uterus and the placenta, which indicates the accumulation of blood with the formation of a retroplacental hematoma, sometimes reaching gigantic proportions. If the exfoliated area is located along the edge of the placenta and is small in size, then a linear echo-negative strip is determined on the echogram at the site of the detachment. With the use of ultrasound placentography, it became possible to conduct dynamic observation of changes in the size and signs of organization of the detachment site.

Echographic diagnosis of premature detachment of a normally located placenta sometimes has to be differentiated from an extended decidua basalis, visualized as an echo-negative space with linear structures up to 1.5 cm thick.Such expansion is usually associated with maternal hypotonia and obstruction of blood flow through dense venous plexuses decidua basalis. Around the edges decidua basalis more compact. The difference is that the expanded space is defined almost over the entire area.

Rice. eleven. Placenta previa. Visualization of placental tissue in the area of the internal os

spare the placenta of the same structure. After rejection of the placenta, this layer is represented only by scraps of the shell.

In some cases, placental cysts are detected in the form of clearly delineated echo-negative formations. Placental calcification is characterized by the presence in its parenchyma of multiple small and large inclusions of increased acoustic density. The placenta acquires a pronounced lobular structure due to the spread of the process to the placental septa (Fig. 12).

Rice. 12. Placental calcification

Noteworthy is the question of changes in the structure of the placenta, its "maturation", during pregnancy. Changes in the structure of the placenta during ultrasound examination during pregnancy are presented in table. 7. In uncomplicated pregnancy, stage I of the structure of the placenta is found mainly from the 26th week of pregnancy, stage II - from the 32nd week, and III - from the 36th week. The appearance of echographic signs of various stages of the structure of the placenta earlier than the established time is regarded as premature "aging" of the placenta.

It was found that with a physiologically proceeding pregnancy, the thickness of the placenta constantly increases in a linear relationship from 10.9 mm at 7 weeks to 35.6 mm at 36 weeks. By the end of pregnancy, its thickness decreases slightly.

Table 7. Ultrasound changes in the placenta depending on the degree of its maturity (P. Grannum et al., 1979)

With Rh sensitization and the development of hemolytic disease, as well as with diabetes mellitus, the thickness of the placenta can increase to 50 mm or more. Placental insufficiency, on the other hand, is characterized by a thinning of the placenta and its premature maturation.

The presented data on the diagnostic capabilities of ultrasound research make it indispensable in clinical practice as a screening method for examining pregnant women for early diagnosis of fetal diseases.

The third screening ultrasound examination is performed at 30-34 weeks in order to identify malformations with late manifestation, as well as to assess the functional state of the fetus (diagnosis of intrauterine growth retardation and hypoxia, as well as the identification of functional reserves of uteroplacental fetal blood flow).

The scope of the examination and the scheme for the third ultrasound examination correspond to those for the second screening, but quite often to assess the functional state of the fetus, a Doppler study of blood flow in the vessels of the mother, fetus and placenta and cardiotocography are required.

DOPPLEROMETRY IN OBSTETRIC PRACTICE

It is generally accepted that the leading pathogenetic mechanism of fetal disorders in various complications of pregnancy and extragenital diseases are hemodynamic disorders in a single functional mother-placenta-fetus system. In most cases, hemodynamic disorders are characterized by the universality and uniformity of changes, regardless of the state of the fetus and the etiopathogenetic factor. In addition, systemic hemodynamic disorders in the mother are observed with such a severe complication of pregnancy as gestosis, as well as with many extragenital diseases.

The first publication on the use of Doppler in obstetrics dates back to 1977, when D. FitzGerald and J. Drumm recorded blood flow velocity curves (CSC) in the umbilical cord artery using a continuous wave probe. For the first time, dopplerometry in Russia was used by A.N. Strizhakov et al. in 1985

High information content, non-invasiveness, relative simplicity, safety and the possibility of use throughout pregnancy, including early gestation, makes this method of blood circulation research indispensable in obstetrics.

The newest method based on the Doppler effect is color Doppler mapping. The high resolution of the method makes it possible to visualize and identify the smallest vessels of the microvasculature, which makes this method indispensable in the diagnosis of vascular pathology, including in perinatology. The first experience of using CDC in obstetric practice is associated with the names of D. Maulik et al. and A. Kurjak (1986). Since 1987 (Kurjak A. et al.), Transvaginal CDC has been used in obstetrics. The CDC provides the ability to study blood flow in the branches of the uterine artery (up to the spiral arteries), terminal branches of the umbilical artery, and the intervillous space. This made it possible to study the features of the formation and development of intraplacental hemodynamics and opened up new prospects for early diagnosis of obstetric complications associated with the formation of placental insufficiency.

The main testimony to conduct a Doppler study of blood flow in the uterine arteries and vessels of the fetus (umbilical artery and its terminal branches, middle cerebral artery, aorta, venous duct) are:

"diseases of a pregnant woman: preeclampsia, hypertension, hypotension, kidney disease, collagen vascular disease, diabetes;

"fetal diseases: intrauterine growth retardation, inconsistency between the size of the fetus and the gestational age, unexplained lack of water, premature maturation of the placenta, multiple pregnancies;

burdened obstetric history: intrauterine growth retardation and fetal distress, preeclampsia and stillbirth in previous pregnancies;

post-term pregnancy.

The most widespread in obstetric practice is a qualitative analysis of the curves of blood flow rates, the indicators of which do not depend on the diameter of the vessel and the magnitude of the angle of insonation. In this case, the ratio between the blood flow velocity in different phases of the cardiac cycle is of primary importance. The most commonly used systolic-diastolic ratio (SDR) (Stuart B. et al., 1980), pulsation index (PI) (Gosling R., King D., 1975), resistance index (IR) (Pourcelot L., 1974).

SDO = MSSK / KDSK,

PI = (MSSK-KDSK) / SSK,

IR = (MSSK-KDSK) / MSSK,

where: MSSK is the maximum systolic blood flow velocity, KDSK is the final diastolic blood flow velocity, and MSS is the average blood flow velocity.

An increase in vascular resistance, manifested primarily by a decrease in the diastolic component of blood flow, leads to an increase in the numerical values of these indices.

Using high-resolution equipment, blood flow is assessed in most fetal vessels (aorta, pulmonary trunk, inferior and superior vena cava, ductus arteriosus, common, internal and external carotid arteries, anterior, middle and posterior cerebral arteries, renal arteries, hepatic and umbilical veins, as well as arteries of the upper extremities).

The most important for diagnosing the state of the placental complex, embryo and fetus, predicting the further development of pregnancy and early diagnosis of its complications is the Doppler study of blood flow in all these vascular links.

With the help of color Doppler mapping, blood circulation in the intervillous space is visualized starting from the 6th week of pregnancy. The spectrum of blood flow in this case has a venous character, with high turbulence and low pulsation. It should be noted that patients with anembryonia and early spontaneous abortions have a higher pulsation of blood flow. This reflects the premature entry of maternal blood into the intervillous space, leading to placental abruption and termination of pregnancy.

Visualization of blood flow in the spiral arteries using the color Doppler mapping technique is possible already from the 6th week of pregnancy, and from the early stages it is characterized by low pulsation and high diastolic velocities. The most pronounced decrease in vascular resistance in the uterine arteries occurs at 12-13 weeks and 20-22 weeks, and in the spiral arteries - at 8-10 and 13-14 weeks of gestation, which reflects the completion of the processes of trophoblast invasion and the completion of gestational changes in the spiral arteries. These periods are critical for the development of the uteroplacental circulation. Evaluation of its parameters at the end of the first trimester of pregnancy makes it possible to predict its further course. The mechanism that ensures the constancy of uterine blood flow during the progression of pregnancy is based on a decrease in pre-placental resistance to blood flow. This is achieved by the process of trophoblast invasion, which consists in degeneration of the muscle layer, hypertrophy of endothelial cells and fibrinoid necrosis of the end portions of the spiral arteries, which is usually completely completed by 16-18 weeks of gestation. Preservation of high resistance of the uterine arteries, due to the violation or absence of invasion of the trophoblast, is the main morphological substrate of disorders of the uteroplacental circulation (Fig. 13).

Normally, CSCs in the uterine arteries after 18-20 weeks of gestation are characterized by the presence of biphasic curves with a high diastolic blood flow velocity. During the second half

Rice. 13. Reverse diastolic blood flow in the umbilical artery of the fetus

In uncomplicated pregnancy, the numerical values of the indices reflecting the resistance of the vascular wall remain fairly stable with a slight decrease towards the end of pregnancy. With an uncomplicated course of pregnancy, the LMS values in the uterine arteries after 18-20 weeks should not exceed 2.4. In the II and III trimesters of pregnancy, the importance of studying the blood flow in the uterine and spiral arteries takes on the character of early diagnosis of preeclampsia and placental insufficiency. The characteristic signs of pathological CSCs in the uterine arteries are a decrease in the diastolic component of the blood flow and the appearance of a dicrotic notch in the early diastole phase, while there is a significant increase in the LMS, IR, and PI values.

As proven by numerous studies and practice, this is of great importance for developing a rational approach to therapy and obstetric tactics. The most studied vessel in obstetric practice is currently the umbilical cord artery (AP). Visualization of the umbilical cord with transvaginal ultrasound is possible in most cases from 7-8 weeks of pregnancy. The analysis of the curves of blood flow velocities in the umbilical artery has the greatest value only starting from the 10th week of pregnancy. The diastolic component of blood flow in the umbilical artery may be absent up to 14 weeks of gestation. In fetuses with chromosomal abnormalities in the period of 10-13 weeks,

Reverse diastolic blood flow occurs, which is not recorded in healthy fetuses. More informative is the definition of the pulsation index in the umbilical artery. An increase in PI and the presence of an expansion of the collar space makes it possible to more reliably diagnose chromosomal abnormalities in the fetus, including trisomies. During the second half of uncomplicated pregnancy, a significant decrease in the indicators of vascular resistance in AP is observed, which is expressed in a decrease in the numerical values of SDO, IR, PI. Before 14-15 weeks of pregnancy, when using a 50 Hz filter, diastolic blood flow is not visualized in most cases. After 15-16 weeks, he is registered constantly. A decrease in the vascular resistance indices in AP during the II and III trimesters of pregnancy indicates a decrease in the vascular resistance of the placenta, which is caused by the intensive growth of its terminal bed associated with the development and vascularization of the terminal villi of the placenta. In uncomplicated pregnancy, the LMS values in the AP should not exceed 3.0. Pathological CSCs in AP are characterized by a decrease in the final diastolic blood flow velocity, up to the complete disappearance or appearance of the retrograde diastolic component, which indicates a significant increase in the peripheral vascular resistance of the fetal part of the placenta. The morphological substrate of this is a decrease in vascularization of the terminal villi of the fruiting part of the placenta and damage to the microvessels of the villi, manifested by obliteration of small muscle arteries in their tertiary trunks.

The value of the study of blood flow in the umbilical cord artery, its terminal branches, uterine and spiral arteries in the II and III trimesters of pregnancy is clearly defined and is widely used in clinical practice both to assess the state of the fetal circulation, and to determine the functioning of the entire fetoplacental system, especially with a threatening termination of pregnancy , gestosis, placental insufficiency, intrauterine infection. For a more accurate and objective Doppler assessment of blood circulation in the mother-placenta-fetus system, a comprehensive accounting of the data obtained is proposed. A.N. Strizhakov et al. (1989) developed a classification of disorders of the uteroplacental and fetal-placental blood flow based on the assessment of CSC in the uterine arteries and AP. At I degree

violations of only uterine (A) (Fig. 14) or only fetal (B) blood flow are noted. II degree characterized by disorders of both uterine and fetal blood flow, which do not reach critical values. At III degree violations of blood flow in the AP reach critical values, expressed by the presence of zero or negative values of the diastolic component of the blood flow. There is a clear, directly proportional relationship between the degree of hemodynamic and the frequency of intrauterine fetal growth retardation, early delivery, cesarean section and the condition of the newborn.

Rice. fourteen. Pathological spectrum of blood flow in the uterine arteries

The greatest attention is drawn to the assessment of fetal hemodynamics and uteroplacental blood flow in placental insufficiency. A typical manifestation of placental insufficiency is intrauterine fetal growth retardation (IUGR). The primary link in the development of IGRP in most cases during the second half of pregnancy is the disturbance of the uteroplacental blood flow. With the simultaneous involvement of two uterine arteries in the process, IUGR is observed in 100% of cases and is more pronounced, and newborns need more intensive treatment and observation.

Doppler assessment of the state of the fetus during intrauterine hypoxia is important. Doppler analysis allows, somewhat earlier than cardiotocography, to diagnose intrauterine fetal hypoxia. The most informative in this case is the study and assessment of the CSC in the fetal aorta. In the pathogenesis of antenatal decelerations, the leading place is occupied by violations of fetal hemodynamics

(especially in the critical state of the fetal-placental blood flow). Timely accurate assessment of the fetus in dynamics is of paramount importance for choosing the optimal timing and method of delivery.

Currently, much attention is paid to the study of blood flow in the veins of the fetus, starting from the first trimester of pregnancy.

The ductus venosus is a vessel that is a direct communication between the umbilical vein and the central venous system, through which a well-oxygenated blood flow is formed. From the end of the first trimester of pregnancy, with normal fetal development, blood flow in the ductus venosus is characterized by a three-phase curve due to different phases of the cardiac cycle: ventricular systole, early ventricular diastole and atrial systole. With the normal development of pregnancy, blood flow in the ductus venosus remains unidirectional throughout all phases of the cardiac cycle. Disturbances of blood flow in the ductus venosus during 10-14 weeks of pregnancy (zero or reverse blood flow in the phase of atrial contraction) are a marker of fetal chromosomal pathology. In the II and III trimesters of pregnancy, changes in venous hemodynamics are secondary to the redistribution of arterial blood flow and are detected in the subcompensated and decompensated state of the fetus. The combination of arterial and venous blood flow disorders is extremely unfavorable for the perinatal prognosis. The study of blood flow in the aorta and cerebral vessels of the fetus acquires significant diagnostic and prognostic value, only starting from 22-24 weeks of pregnancy, since before this period the existing disorders are not detected due to the large compensatory capabilities of fetal hemodynamics. Changes in blood flow in the fetal aorta, characterized by a decrease in the diastolic component of blood flow, reflect the degree of impairment of fetal hemodynamics. They should be considered as a consequence of an increase in the resistance of the peripheral vascular bed of the fetus and a compensatory decrease in the resistance of cerebral vessels in conditions of progressive intrauterine hypoxia. The most unfavorable is zero or reverse diastolic blood flow in the fetal aorta, reflecting its critical condition.

An increase in cerebral blood flow, in turn, is a manifestation of compensatory centralization of fetal circulation.

with intrauterine hypoxia in conditions of reduced placental perfusion. An increase in the peripheral vascular resistance of the brain is a risk factor for a complicated course of the neonatal period, leads to a decrease in the compensatory capabilities of the newborn and disrupts adaptation processes.

Dopplerometry with gestosis is of great clinical importance. There was a direct proportional relationship between the severity of gestosis, on the one hand, and the frequency and severity of blood flow disturbances in the uterine arteries, on the other. In severe forms of preeclampsia, changes in the KSK in the uterine arteries occur in parallel with disturbances in blood flow in the AP. Violations of the uteroplacental-fetal blood flow are in direct proportion to the severity of preeclampsia and can be considered as an objective indicator of the severity of the disease, regardless of its clinical manifestations. The most unfavorable prognostic signs are abnormalities of the CSC in both uterine arteries, the appearance of a dicrotic notch, and pronounced disturbances in fetal hemodynamics. Doppler analysis allows predicting the occurrence of gestosis and IUGR in the third trimester based on the detection of pathological CSCs in the uterine arteries in the second trimester of pregnancy. The study of renal and cerebral hemodynamics of pregnant women is also important in gestosis. The formation of the uteroplacental blood circulation in uncomplicated pregnancy is accompanied by an increase in renal blood flow, especially at 13-18 weeks. With gestosis, there is a progressive decrease in renal hemodynamics, depending on the severity of the disease and the severity of clinical manifestations.

To assess the severity of preeclampsia, Doppler blood flow in the internal carotid artery system is performed. A feature of cerebral hemodynamics in pregnant women is a decrease in peripheral vascular resistance in the internal carotid artery system during uncomplicated pregnancy and an increase in cerebral vascular resistance during gestosis. A significant increase in resistance in the basin of the internal carotid artery (especially the appearance of retrograde blood flow in the supra-block artery) is a prognostically unfavorable sign in relation to the development of preeclampsia and eclampsia.

Thus, knowledge of the features of the formation and development of the uteroplacental, fetal-placental and fetal blood

votokov makes it possible not only to assess the state of the fetus in the second half of pregnancy, but also to assess its anatomical features, diagnose malformations of the vascular system, and identify markers of chromosomal pathology already in the first trimester of pregnancy. This allows for timely diagnosis of clinically significant abnormalities in the development of the fetus and decides on the advisability of prolonging pregnancy or choosing the optimal obstetric tactics. In addition, the use of Doppler analysis of blood flow in the mother's vessels (uterine and spiral arteries, cerebral and renal arteries, assessment of central hemodynamic parameters) makes it possible to predict the development of preeclampsia, which makes it possible to carry out preventive measures that contribute to improving pregnancy outcomes for the mother and fetus.

ANTE- AND INTRANATAL FETAL CARDIOTOCOGRAPHY

In modern obstetrics, along with traditional methods for assessing the condition of the fetus, ultrasound devices are widely used, which allow cardiac monitoring during pregnancy and childbirth. The behavioral reactions of the fetus and the nature of its cardiac activity are closely related to its intrauterine state and the duration of pregnancy. Reactions from the fetus to the effects of external factors, to changes in its own metabolism are quite typical, which allows them to be systematized to assess its state. Intensive monitoring of fetal cardiac activity expanded diagnostic capabilities, made it possible to timely identify indications for emergency delivery and thereby reduce perinatal mortality rates.

Modern cardiac monitors are based on the Doppler principle, the use of which allows registering changes in the intervals between individual cycles of fetal cardiac activity, which are converted into changes in heart rate and are displayed in the form of light, sound, digital signals and graphic images. In modern fetal monitors, ultrasonic transducers with a frequency of 1.5 and 2.0 MHz are usually used. During the cardiotocographic examination of the patient

it is assumed that they hear fetal heart sounds, but this is nothing more than a frequency shift of the reflected ultrasonic waves. Modern devices are also equipped with sensors that simultaneously register uterine contractile activity and fetal movements. In clinical practice, the most widespread are external sensors, the use of which has practically no contraindications and is devoid of any complications or side effects.

An external ultrasound probe is placed on the anterior abdominal wall of the pregnant woman at the point where the fetal heart sounds are best heard. In modern fetal cardiac monitors, an indicator is provided that demonstrates the quality of registration of fetal heartbeats. A layer of special gel is applied to the surface of the sensor to ensure optimal contact. An external strain gauge sensor is applied in the area of the right corner of the uterus. No gel is applied to its surface. After attaching the sensor, it is necessary to establish the optimal basal registration level. The use of external cardiotocography (CTG) allows continuous monitoring of the fetal cardiac activity for a long time. In addition to sensors, fetal monitors are equipped with a special device for recording fetal movements. With its help, the patient independently notes each episode of movement. Cardiotocographic examination can be carried out in the position of the pregnant woman on her back, but it is better with a slight turn to the left side. To obtain the most accurate information about the state of the fetus, the recording should be made for at least 40-60 minutes. This duration is associated with the presence of periods of sleep and activity in the fetus. When using internal sensors, a special spiral electrode is applied to the skin of the fetal head, and a catheter is inserted intraamnially to register contractile activity.

Carrying out cardiotocography is considered justified only from the 32nd week of pregnancy. When using devices with automatic analysis of cardiotocograms, the study can be carried out starting from the 26th week of pregnancy.

Indications for cardiotocographic research:

Complicated obstetric history (perinatal loss, intrauterine growth retardation, premature birth, etc.);

Diseases of a pregnant woman (hypertension, diabetes mellitus, kidney disease, systemic diseases) and complications of pregnancy (Rh immunization, gestosis);

Multiple pregnancy;

Postterm pregnancy;

Reducing the number of movements felt by the pregnant woman;

Intrauterine growth retardation;

Low water;

Premature maturation of the placenta;

Curable congenital malformations of the fetus;

Previous suspicious or abnormal cardiotocogram;

Hemodynamic disorders in the mother-placenta-fetus system - according to Doppler data.

The task of monitoring during childbirth is to timely recognize the deterioration of the fetus, which makes it possible to adequately correct it, and, if necessary, accelerate delivery. When characterizing the state of the fetus in labor, the following parameters of the cardiotocogram are assessed: the basal rhythm of the heart rate, its variability, 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.

The study of CTG begins with the determination of the basal rhythm. Basal rhythm is understood as the average value between the instantaneous values of the fetal heart rate in the interval between contractions; in this case, the values of accelerations and decelerations are not taken into account. The basal rate is calculated over a 10-minute interval. The normal basal rhythm is 120-160 beats / min (on average, 140-145 beats / min). Basal rhythm below 120 beats / min is regarded as bradycardia, above 160 beats / min - as tachycardia. In the first stage of labor, tachycardia is more common and more pronounced. In this regard, moderate (161-180 beats / min) and severe (above 181 beats / min) tachycardia are distinguished. The severity of tachycardia corresponds to the severity of fetal hypoxia.

Bradycardia testifies to a decrease in the reserve capacity of the fetus. Persistent bradycardia can be a sign of a congenital malformation of the fetal heart. Just like tachycardia, bradycardia is divided by severity into moderate

ny and pronounced (respectively 119-100 and less than 100 beats / min). It should be noted that the basal rhythm is one of the most inert parameters of fetal cardiac activity, therefore, when assessing CTG, it is necessary to take into account other pathological changes, which significantly increases the diagnostic value of the method.

When characterizing the basal rhythm, it is necessary to assess its variability, i.e. frequency and amplitude of instantaneous changes in fetal heart rate (instantaneous oscillations). The counting of the frequency and amplitude of instantaneous oscillations is carried out during 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 variability of the basal rhythm is most widespread: mute (monotonous) rhythm is characterized by a low amplitude - 0-5 beats / min; slightly undulating - 5-10 beats / min; undulating - 10-25 beats / min; saltatory - 25-30 beats / min. The variability of the amplitude of instantaneous oscillations can be combined with a change in their frequency (normally 7-12 oscillations per minute).

During the physiological course of labor, all types of variability of the basal rhythm can occur, but the most often present are slightly undulating and undulating rhythms. With a complicated course of labor, it is necessary to pay attention to the appearance of a mute and saltatory type of variability of the basal rhythm, especially in combination with tachycardia or bradycardia. The mute type is considered the most unfavorable, especially with a simultaneous decrease in the amplitude (less than 3 beats / min) and the frequency of oscillations (less than 6 oscillations in 1 min). Such a curve usually indicates a deep hypoxic effect on the central nervous system and the fetal myocardium and is essentially preagonal (terminal). With an uncomplicated course of labor, the mute type of variability in the basal rhythm may be due to the effects of drugs and sedatives.

When analyzing CTG, it is necessary to pay attention to periodic slow accelerations (accelerations) of the basal rhythm, which reflect the degree of compensatory capabilities of the fetal cardiovascular system. In the physiological course of labor, acceleration is observed almost constantly with a frequency of 4-5 or more in 30 minutes,

their duration is 20-60 s, the amplitude is more than 15 beats / min. Periodic accelerations occur early in labor and are associated with uterine contractions or compression of the umbilical cord. Sporadic acceleration is most often associated with fetal motor activity. A decrease in the frequency of accelerations or, even more so, their absence is an unfavorable prognostic sign.

Evaluation of slow waves of decrease in the basal rhythm is of great importance for diagnosing the state of the fetus. The appearance of decelerations indicates certain pathological changes in the fetoplacental system.

For the diagnostic use of CTG W. Fischer (1973) proposed a scale in which the main indicators are assessed by a point system. The score of 8-10 points characterizes the satisfactory condition of the fetus, 6-7 points - compensated and less than 6 - decompensated fetal disorder (Table 8).

Quite a lot of other systems for assessing the state of the fetus according to cardiotocography data have been proposed (Gauthier E.S, 1982; FIGO classification, 1987), as well as special equations for determining the indicator of the state of the fetus (Demidov V.N., 1983).

It should be emphasized that when using CTG in childbirth, it is necessary to observe the monitoring principle, i.e. constant dynamic assessment of CTG throughout childbirth, taking into account the maximum number of indicators. The diagnostic value of the method increases with a careful comparison of CTG data with the obstetric situation and other criteria for assessing the condition of the fetus.

Functional tests are of great help in assessing the state of the fetus and the reserve capabilities of the fetoplacental system. A large number of methods for carrying out functional tests have been developed (atropine, euphyllin tests, load test, breath holding). When conducting antenatal CTG, stress (oxytocin) and non-stress tests are currently the most common.

The essence of the oxytocin test is to study the reaction of the fetal cardiovascular system in response to uterine contractions caused by the administration of an oxytocin solution. For the test, an oxytocin solution containing 0.01 U in 1 ml of isotonic sodium chloride solution is injected intravenously. The rate of administration is 1 ml / min. The test can be interpreted if at least 3-4 contractions have occurred within 10 minutes, with sufficient compensatory

Table 8. CTG assessment scale according to W. Fischer et al. (1973)

the capabilities of the fetoplacental system in response to uterine contraction, a mild short-term acceleration is observed. The absence of a reaction or the appearance of slow decelerations in response to the induced contractions of the uterus indicates placental insufficiency. The oxytocin test has a number of contraindications (threat of termination of pregnancy, scar on the uterus, pathology of placenta attachment), therefore, it has rarely been used recently.

The so-called non-stress test is highly informative. Its essence lies in the study of the reaction of the cardiovascular system of the fetus in response to movement. Normally, fetal movements are accompanied by a short-term acceleration of the basal rhythm (slow acceleration). In this case, the test is considered positive. In more than 99% of cases, a positive non-stress test is a reliable criterion for the well-being of the fetus. In the event that, in response to fetal movements, accelerations occur in less than 80% of cases, the test is considered doubtful. In the absence of a reaction of the fetal cardiac activity in response to movement, the test is considered negative, which indicates tension and depletion of compensatory reactions. The test can be false negative if the study is carried out during the period of physiological rest of the fetus. In this case, the study must be repeated.

The diagnostic value of antenatal CTG occurs only with a dynamic study. In these conditions, almost any pathological therapy can be assessed as a functional test. The lack of positive dynamics on CTG, and even more so negative against the background of the treatment, indicate the progression of placental insufficiency and raise the question of the advisability of further prolongation of pregnancy. The question of the time and method of delivery should be resolved not only on the basis of a detailed dynamic analysis of antenatal CTG, but also taking into account the entire obstetric situation and data from other additional research methods.

However, the visual interpretation of the obtained cardiotocograms is not devoid of the factor of subjectivity, it is difficult to reproduce both between different specialists and at different times with the same specialist. In this regard, in recent years, many clinics around the world have attempted to develop various computer programs for the assessment of cardiotocographic curves. The most widely used computer system is 8000 (Oxford, UK). It was developed by Professors G. Dawes and C. Redman (1991). The program allows you to conduct a detailed analysis of many parameters of the cardiotocogram in the antenatal period in real time, calculate various indices and compare them with standard indicators. In addition, in 1995, they also proposed System 8002, which makes it possible to correlate indicators with gestational age, which significantly increased the diagnostic value of the method.

Evaluation system for cardiotocograms called Dawes / Redman criteria, includes:

Assessment of the variability of the basal rhythm (the number of episodes of high and low variability, which reflect the state of the fetus better than the presence of accelerations);

STV indicator (in the normal state of the fetus - more than 3 ms);

Assessment of the basal heart rate (normally within 115-160 beats / min).

The criteria for the normal state of the fetus, according to G. Dawes and C. Redman, is the absence of deep decelerations and the presence of at least 1 episode of movement or acceleration in 10 minutes of recording.

The advantages of computerized assessment of cardiotocograms include:

Early terms of the study (starting from 26 weeks of pregnancy);

Objectivity in the assessment of fetal cardiac activity;

Obtaining data during dynamic monitoring of the state of the fetus in the form of a standard report;

A short study duration (in more than 50% of observations, the Dawes / Redman criteria are recorded after 10 minutes of recording, and only 17% require recording within 60 minutes).

Thus, cardiotocography, especially in the presence of computer analysis, provides valuable information about the condition of the fetus.

THE CONCEPT OF BIOCHEMICAL SCREENING

In 1984 L.R. Merkatz showed a correlation between low values of alpha-fetoprotein (AFP) in the maternal blood serum and the presence of trisomy on 21 pairs of chromosomes in the fetus. Since then, the diagnostic value of determining a number of other biochemical markers has been studied in order to identify malformations and chromosomal pathology of the fetus. These include the β-subunit of human chorionic gonadotropin (hCG) and unconjugated estriol (NE), the concentration of which in the maternal serum increases in the presence of trisomies in the fetus. In Russia, the formation of a risk group among pregnant women by birth of children with chromosomal diseases and some congenital malformations (spina bifida, anencephaly, omphalocele, etc.) is carried out according to the results of a mother's blood test for AFP and hCG at 16-20 weeks of pregnancy (the so-called duplex test). In a number of countries, it is more accepted to carry out the so-called triplex test, i.e. determination of all of the above biochemical markers, which increases the diagnostic accuracy of serum screening. It should be remembered that the level of AFP and especially of chorionic gonadotropin can change for other reasons (incorrect determination

division of gestational age, multiple pregnancy, racial characteristics of pregnant women), which leads to a false positive diagnosis of genetic inferiority of the fetus.

In the late 80s. XX century data on the nature of changes in AFP and NE in early pregnancy gradually began to accumulate. It was found that with trisomy on 21 pairs of chromosomes (Down's syndrome), deviations in the levels of these markers can be registered as early as 9-11 weeks. H. Cuckle, N. Wald, G. Barkai (1988) established the fact that in trisomies the medians of traditional biochemical markers practically do not differ from the medians at the time of traditional screening (16-22 weeks) and are: for AFP - 0.75 MoM (at 16-22 weeks - 0.72 MoM), for NE - 0.73 MoM (0.72 MoM), for total hCG - 1.90 MoM (2.01 MoM). Simultaneously with the study of the dynamics of well-known markers, a search was carried out for other early markers of chromosomal pathology. Particular attention was paid to the study of PAPP-A (plasma protein associated with pregnancy - pregnancy associated plasma protein A), since most of the studies carried out in the 90s. XX century, showed a high diagnostic value of the determination of β-hCG and PAPP-A. Normally, in the interval from 9 to 13 weeks, the concentration of PAPP-A progressively increases from 1.48 to 4.71 MoM, and free β-hCG first increases, and by the end of the first trimester it decreases. With trisomies, there is an increase in the level of the second and a significant decrease in the level of PAPP-A. D. Wheeler, M. Sinosich (1998) concluded that the end of the first trimester is the optimal time for screening using PAPP-A and free β-hCG, and that this test can also be used to predict unpromising pregnancies. The combination of determination of biochemical markers, the age of a pregnant woman over 35 and an assessment of the thickness of the collar space (detectability of trisomies - up to 90%) has a particular prognostic value in identifying the chromosomal pathology of the fetus in the first trimester.

INVASIVE METHODS FOR ASSESSING FETAL CONDITION

Embryoscopy- examination of the embryo using an optical device up to 12 weeks of gestation for the purpose of visual assessment of its organs. The first attempt to visualize the fetus directly in the uterine cavity using a hysteroscope in 1954 was made by

J. Westin. Over the past half century, optical technology has undergone significant changes and today prenatal medicine has miniature devices with high resolution and excellent quality optics. The main indication for endoscopic studies in the early stages of pregnancy is the high risk of congenital and hereditary pathology in the fetus, which cannot be detected using traditional echography and does not give characteristic changes in cytogenetic, biochemical or DNA analyzes. There are reports in the literature on the possibilities of using embryoscopy for the diagnosis of fetal pathology. M. Dommergues et al. in 1995 published data on the diagnosis of Meckel-Gruber syndrome at 10-11 weeks based on the detection of postaxial polydactyly. The observations of diagnostics of polydactyly, clubfoot, encephalocele, microgenia, clefts and other facial anomalies in the period from 8 to 13 weeks are described. In addition, intra-amnial endoscopic procedures can be used not only for visual assessment of organs and parts of the fetus, but also for the purpose of obtaining material for genetic research. The main disadvantage of studies in the first trimester with the use of optical instruments is the high risk of complications. For example, the frequency of abortion is 12-35%, which limits the application of the method in wide clinical practice. Until now, in the literature on endoscopic methods, there are discussions about the possible damage to the eyes of the fetus by bright light used during the procedure. The presence of endoscopic methods in the arsenal of prenatal medicine allows us to hope for their expansion in clinical practice.

Department of Obstetrics and Gynecology? 2 MMA them. THEM. Sechenov (Strizhakov A.N., Davydov A.I., Sokolov A.V., 2003) proposed a scheme for prenatal diagnosis in early pregnancy using transvaginal echography and transcervical embryoscopy. The study is recommended to be carried out in two stages. At the 1st stage all pregnant women in the first trimester undergo transvaginal embryosonography, during which embryophetometric parameters are measured, followed by a qualitative assessment of the anatomical structures of the embryo / fetus, identification of markers of chromosomal pathology (the thickness of the collar space, correspondence of the coccygeal-parietal

size, gestational age, length of the fetal nasal bones, fetal heart rate), as well as dopplerometry (study of blood flow in the ductus venosus, artery and vein of the umbilical cord). At the 2nd stage all examined patients underwent endoscopic visualization of the ovum - transcervical embryoscopy, which is carried out using the endovideo complex, which projected the image onto the monitor screen at 6-8x magnification (Fig. 15).

Rice. 15. Transcervical embryoscopy. 10 weeks gestation. Formed the upper and lower limbs of the fetus

Amnioscopy. To study the state of amniotic fluid and the fetus during pregnancy, amnioscopy is used - a transcervical examination of the lower pole of the fetal bladder. This method was suggested by E.M. Saling in 1962. An amnioscope with a length of 20-25 cm and a diameter of 12-20 mm is used for the study, depending on the dilatation of the cervix. The examination is carried out on a gynecological chair in the position of a woman with her legs brought to her stomach. Under aseptic conditions, an amnioscope with a mandrel is introduced into the cervical canal to the lower pole of the ovum, then the mandrel is removed and the lighting system is turned on. With an uncomplicated course of pregnancy, a sufficient amount of light, transparent, opalescent amniotic fluid with the presence of a white cheese-like lubricant is released. Lack of water, detection

meconium and their greenish color indicate fetal hypoxia, the detection of brown amniotic fluid indicates intrauterine fetal death.

Amnioscopy should be performed from the 37th week of pregnancy with suspicion of intrauterine fetal death and its hemolytic disease, low location of the placenta, with gestosis, in elderly primiparas, burdened obstetric and gynecological history, chronic placental fetal insufficiency, fetal cardiac anomalies, prolonged pregnancy.

With amnioscopy, complications can be observed, in particular rupture of the membranes, bleeding as a result of trauma to the mucous membrane of the cervical canal or damage to the vessels at the site of fetal detachment, infection of the birth canal, and the occurrence of premature birth.

Amnioscopy is contraindicated in placenta previa, inflammatory diseases of the vagina and cervix.

Indications for examination using invasive methods in the first trimester differ little from those in the second trimester of pregnancy. According to the traditional principles of the formation of a risk group among pregnant women, threatened by the birth of children with congenital and hereditary pathology, invasive studies should be offered:

Pregnant women aged 35 and over;

Patients with a burdened history (birth of children with chromosomal abnormalities or with monogenic diseases subject to prenatal diagnosis);

Families in which one of the spouses is a carrier of a chromosomal rearrangement or both spouses are carriers of a gene mutation;

Pregnant women who have ultrasound markers of chromosomal pathology (for example, expansion of the collar space);

Pregnant women who have abnormalities in serum blood markers during screening biochemical studies.

There are several classifications of invasive research methods during pregnancy:

By the nature of the access (transcervical, tranabdominal);

By the technique of obtaining the material (by aspiration, by biopsy);

By the nature of the control over the procedure (under ultrasound control, under the control of endoscopic devices);

By the nature of the material obtained (chorionic villi, amniotic fluid, blood from the umbilical cord).

* 9-12 weeks- Chorionic villus sampling (transcervical or transabdominal).

13-14 weeks- early amniocentesis is possible, but the risk of complications when using this method is quite high. Spontaneous abortion is observed in 3.8 to 5.3%, and failures of culturing cells obtained from amniotic fluid are about 11-12%.

15-17 weeks- amniocentesis and early placentocentesis.

18 weeks or more- cordocentesis, amniocentesis, placentocentesis.

All invasive procedures in Russia are regulated by the Order of the Ministry of Health dated December 28, 2000. Invasive interventions are carried out only with the consent of the pregnant woman under ultrasound control after a mandatory gynecological examination of the woman in her satisfactory condition. Relative contraindications for invasive interventions include in the first trimester a threatening termination of pregnancy with bloody discharge, the presence of multiple myomatous nodes in the uterus, preceding laparotomy and surgery on the uterus, inflammatory diseases with an increase in body temperature. The same factors are taken into account when carrying out cordocentesis, although, according to some authors, there are no absolute contraindications for taking blood from the umbilical cord vein of the fetus. Among the possible complications of invasive procedures, first of all, bleeding and bleeding (1-4%), intrauterine infection and sepsis (0.2-0.5%) should be attributed. Early chorionic villus aspiration is associated with the risk of limb reduction and oromandibular hypogenesis. Complications of cordocentesis include transient bradycardia (in 18.3%), bleeding from the puncture site, inflammatory complications (0.6-2.91%),

loss of fetuses after the procedure (2-2.5%). As can be seen from the data presented, despite the high diagnostic value, invasive procedures require a thorough assessment of both the possible risk of having a sick child and the risk of pregnancy complications with a normal fetal karyotype.

Amniocentesis. In order to obtain amniotic fluid for research, a puncture of the amniotic cavity is performed - amniocentesis. For this, several methods of amniotic fluid intake are used: transabdominal, transvaginal, transcervical. Amniocentesis is performed starting from the 16th week of pregnancy. It is used to assess the maturity of the fetal lungs, latent intrauterine infection, with suspicion of congenital malformations of the fetus, its hemolytic disease, prolonged pregnancy, chronic fetal hypoxia (Fig. 16).

Rice. 16. Amniocentesis

With the help of amniocentesis, the biochemical and bacteriological composition, the acid-base state of the amniotic fluid are studied, and genetic diseases are diagnosed, which makes it possible to develop tactics for further pregnancy management.

Chorionic villus sampling. Operation, the purpose of which is to obtain chorionic villus cells for karyotyping the fetus and determining chromosomal and gene abnormalities (including the determination of hereditary metabolic disorders). Sampling is carried out transcervically or transabdominally in the period from 8 to 12 weeks of pregnancy 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, under visual control, is advanced to the placenta localization and further between the uterine wall and the placental tissue. Then, with a 20 ml syringe containing 3-4 ml of culture medium with heparin connected to a vacuum pump, the chorionic tissue is aspirated and further examined. Chorionic tissue sampling is also possible in cases of dichorionic twins. Complications of chorionic villus sampling can be intrauterine infection, bleeding, spontaneous miscarriages, and the formation of hematomas. Later complications include premature birth, low birth weight (<2500 г), пороки развития плода. Перинатальная смертность достигает 0,2-0,9%.

Cordocentesis. An operation, the purpose of which is to obtain fetal blood samples by puncture of the umbilical cord vein under ultrasound control, while fast karyotyping of the fetus and immunological studies are possible. Preliminary, a thorough ultrasound examination is carried out to determine the signs of fetal life, the localization of the placenta, the position and type of position of the fetus, the volume of amniotic fluid. The puncture site and the trajectory of the puncture needle insertion are determined. Then, after the treatment of the anterior abdominal wall with an antiseptic solution, under local anesthesia, the anterior abdominal wall is punctured with a needle connected to an ultrasound transducer. Usually, 2 ml of fetal blood is taken from the umbilical cord vein with a syringe connected to a puncture needle. After removing the needle, ultrasound observation of the fetus is carried out for another 4-5 minutes to exclude possible bleeding. After the operation, the woman is in the hospital for another 6-12 hours. Before discharge, ultrasound and cardiotocography are repeated (after 32 weeks). It is possible to obtain a "pure" (without admixture of mother's blood) portion of fetal blood in 95-97%. Relative contraindications for cordocentesis are oligohydramnios, polyhydramnios, poor fetal location. Potential complications(1-2%) -

chorionamnionitis, rupture of amniotic fluid, Rh immunization, fetal bleeding, hematoma of umbilical cord vessels, intrauterine growth retardation.

ELECTRO- AND PHONOCARDIOGRAPHY OF THE FRUIT

Currently, one of the fairly common methods for assessing fetal cardiac activity are electrocardiography (ECG) and phonocardiography (PCG). Distinguish between direct and indirect fetal ECG. An indirect ECG is performed when electrodes are placed on the anterior abdominal wall of a pregnant woman. This method is used mainly in the antenatal period. With this type of registration, the ECG curve consists only of the ventricular complex, sometimes the P wave is recorded. An indirect ECG is used after 32 weeks of pregnancy. An ECG is recorded when the electrode is applied directly to the fetal head during childbirth when the cervix is opened by 3 cm or more. Direct ECG is characterized by the presence of an atrial wave R, ventricular complex QRS and T.

When analyzing the antenatal ECG, the heart rate, the nature of the rhythm, the size and duration of the ventricular complex, as well as its shape are determined. Normally, the fetal heart rate is correct, the heart rate ranges from 120 to 160 beats / min. Barb R is pointed, the duration of the ventricular complex is 0.03-0.07 s, the voltage ranges from 9 to 65 μV, with an increase in the gestational age, its gradual increase is noted. Direct recording allows you to evaluate all ECG indicators. At the end of pregnancy, the duration of the prong R is 0.06-0.07 s, the interval P-Q- 0.08-0.12 s, interval S-T- 0.04-0.05 s, teeth T- about 0.14 s.

PCG is recorded when the microphone is placed at the point of greatest listening to the fetal heartbeat. A phonocardiogram is usually represented by two groups of oscillations that reflect I and II heart sounds, sometimes III and IV sounds are recorded. Fluctuations in the duration and amplitude of heart sounds are very variable in the third trimester of pregnancy and are on average: I tone - 0.09 s (0.06-0.13 s), II - 0.07 s (0.05-0.09 s ).

The most informative is the simultaneous registration of the ECG and PCG of the fetus and their comparison, which makes it possible to conduct

denya phase analysis of cardiac activity. The phase of asynchronous contraction, mechanical systole, total systole and diastole are calculated. The phase of asynchronous contraction is detected between the onset of the wave Q and I tone with a duration of 0.02-0.05 s. Mechanical systole is the distance between the onset of I and II tones and lasts 0.15-0.22 s. The total systole includes mechanical systole and the phase of asynchronous contraction and is 0.17-0.26 s. Diastole is calculated as the distance between II and I tone, having numerical values in the range of 0.15-0.25 s. It is also important to calculate the ratio of the duration of total systole to the duration of diastole, which averages 1.23 s at the end of an uncomplicated pregnancy.

The use of ECG and PCG has an essential role in the diagnosis of fetal hypoxia and umbilical cord pathology. Violation of the conduction of the heart rhythm during fetal hypoxia is characterized by lengthening and changes in the P wave, an increase in the interval P-Q, as well as the ventricular complex up to 0.06 s and more. In addition, intrauterine fetal hypoxia is characterized by a change in the structure of the cardiac complexes: the segment becomes flat or negative S-T, splitting of the tooth appears R and etc.

Phase analysis of cardiac activity also allows to establish hypoxic damage to the fetal myocardium. Since changes in the contraction phases occur earlier than other myocardial disorders, special attention should be paid to the duration of mechanical systole. With intrauterine hypoxia, due to a violation, first of all, of the conductivity and contractility of the heart muscle, there is a deviation of the duration of the mechanical systole from normal values by more than ± 0.02 s.

With hemolytic disease of the fetus, diastole lengthening, lengthening and moderate decrease in the ventricular complex are often noted, which indicates a violation of intraventricular conduction. In the edematous form, a sharp decrease in the amplitude and tones of the QRS complex is found due to pronounced dystrophic changes in the myocardium. The features of fetal PCG in severe disease include the appearance of heart murmurs.

Pathological changes in the umbilical cord in the antenatal period are characterized by the appearance of systolic murmur and uneven amplitude of heart sounds. With a post-term pregnancy

there is an increase in the complex QRS, as well as deformation and splitting of the tooth R.

With the use of ECG and PCG, it has also become possible antenatally to diagnose many congenital cardiac arrhythmias. It should be noted that if sinus tachycardia or extrasystole is detected as an isolated phenomenon, then this usually does not indicate a violation of the fetus. In case of serious rhythm disturbances (complete atrioventricular block), congenital heart defects are noted in more than 50% of cases.

NON-INVASIVE METHODS OF FETAL CARIOTYPING

In recent years, due to the presence of complications during invasive procedures aimed at obtaining fetal cells for subsequent direct genetic research, there has been increasing interest in a new non-invasive approach to prenatal diagnostics - the study of fetal cells in the peripheral blood of pregnant women. E. dayton, W. Feldhays in 1964 showed that from the early stages of normal pregnancy, there is a process of transplacental transfer of plasma, blood cells and trophoblasts of the fetus into the mother's bloodstream. Cells of the myeloid series (the so-called white blood) and trophoblasts can be deposited in the hematopoietic organs of the mother and persist in her bloodstream for a long time after childbirth. Cells of the erythroid germ (fetal erythroblasts) are not preserved in the mother's body and should not be present in the blood of a healthy adult, therefore erythroblasts are the optimal object for genetic research of the fetus in a non-invasive approach to prenatal diagnosis. The concentration of fetal cells in the mother's blood cells is very low - one nuclear cell is found among 10 5 -10 8 nuclear cells in the mother's blood. This state of the maternal organism is usually denoted by the term "microchimerism", the presence of which during pregnancy creates a certain tolerance of the mother towards the developing fetus. The low concentration of fetal cells in the mother's blood requires multi-stage and highly sensitive methods of enrichment, detection and analysis for their use for diagnostic purposes. Due to the fact that the background frequency of somatic aneuploid cells

the current in a normal human body does not exceed 1-2%, the detection of a larger number of cells with an abnormal karyotype makes it possible to diagnose chromosomal aberration in the fetus.

In connection with the absolute safety of this method for the mother and fetus, researchers are showing increasing interest in it, since when proving its reliability and reliability in the future, this approach can be considered as a potential one when conducting prenatal genetic studies. The most commonly used techniques include sequential adherence to several stages. The mother's peripheral blood is preliminarily centrifuged in a density gradient and a mononuclear cell fraction enriched in fetal erythroblasts is obtained. Further, the separation of fetal erythroblasts is carried out by three methods: using positive flow-through fluorescently activated cell sorting (FAX) with monoclonal antibodies CD71 and GPA, negative magnetically activated cell sorting (MAX) with monoclonal antibodies CD45 two-stage centrifugation in two density gradients. Fetal cells are detected by the FISH method with a Y-chromosome-specific probe, as well as with DNA probes at certain centromeric regions of chromosomes. Despite the fact that fetal cells present in the blood of pregnant women can be isolated by all methods, they differ significantly in terms of labor intensity, cost and reproducibility. At the same time, many researchers have noted a significant individual variability in the concentration of fetal cells in the mother's blood. In addition, when trying to use cells of the fetal lymphoid series, their ability to be deposited in the hematopoietic organs of the mother, to divide in them and persist in the mother's blood for a long time (up to 27 years) after childbirth was noted. This is the main reason for diagnostic errors, due to which the study of fetal lymphocytes is limited by parity and is possible only during the first pregnancy in women. Convincing results were obtained practically only for antenatal non-invasive fetal sex determination in cases of sex-linked diseases, while the diagnostic efficiency, according to various authors, was 87.5-100%.