During the physiological course of gestation, the condition of the embryo is assessed based on:
The results of comparing the size of the uterus and embryo with the gestational age;
Auscultation of fetal heart sounds at each visit to a pregnant woman's antenatal clinic:
Motor activity of the fetus;
The results of ultrasound, which is performed at gestational ages of 18-22 weeks, 32-33 weeks and before childbirth (to determine compliance biophysical profile embryo and degree of maturity of the placenta and gestational age).
In case of complicated gestation, assessment of the condition of the embryo is included in the complex of inpatient analyzes of the pregnant woman, aimed at diagnosing her disease, oxygen deficiency of the embryo and determining the degree of its severity.
To diagnose oxygen deficiency of the embryo, you need:
Assessment of fetal cardiac activity:
Assessment of the motor activity of the embryo;
Amnioscopy;
Ultrasound of the embryo and placenta.
The cardiac activity of the fetus is assessed based on the results of auscultation of fetal heart sounds and cardiotocography (CTG). Auscultation of the heart sounds of the fetus is carried out during each examination of a pregnant woman, in the first stage of labor - every 15-30 minutes and outside uterine spasms, in the second stage of labor - after any uterine spasms. The frequency, rhythm and sonority of the fetal heart sounds are assessed. Tachy or bradycardia, arrhythmia, dull or muffled fetal pulse are clinical signs oxygen deficiency.
Ante- and intrapartum cardiotocography makes it possible to assess the heart rate of the fetus against the background of contractile activity of the uterus and motor activity of the embryo. Changes in basal rate, heart rate variability, acceleration and deceleration reflect the state of the embryo and may be signs of oxygen deficiency.
The motor activity of the embryo is assessed by counting the number of movements of the embryo in 30 minutes in the morning and evening. Normally, 5 or more movements of the embryo are recorded in 30 minutes. By evening, in healthy pregnant women, the motor activity of the fetus increases. With the beginning of oxygen deficiency of the embryo, an increase and increase in movements are observed, with progressive oxygen deficiency - a decrease and weakening, followed by a cessation of movements of the embryo. In case of chronic oxygen deficiency of the embryo, there is an excessive increase or sharp decrease in the difference between the number of movements in the morning and the number of movements in the evening.
The reaction of the embryo's heartbeat to its motor activity can be objectively recorded by CTG (myocardial reflex).
Amnioscopy (transcervical examination of the lower pole of the embryonic bladder) is performed using an amnioscope in the absence of contraindications (placenta previa, colpitis, endocervicitis), but during gestation (after 37 weeks) and in the first stage of labor. Normally, there is a sufficient amount of light, transparent amniotic fluid; in case of oxygen deficiency of the embryo, there is a small amount of greenish water and lumps of meconium.
Ultrasound examination allows us to identify the syndrome of delayed embryo formation, fetoplacental insufficiency, on the basis of which it is possible to establish chronic intrauterine hypoxia of the embryo.
To clarify the severity of oxygen deficiency in the embryo, it is necessary to use:
CTG with functional (stress) tests;
Ultrasound with Doppler sonography;
Determination of the biophysical profile of the embryo, ultrasound placentography;
Amnion biopsy;
Biochemical studies of placenta enzymes and indicators of acid-base balance of the embryo;
Hormone level studies.
CTG with functional (stress) tests is performed in order to timely identify the compensatory capabilities of the embryo. It is possible to conduct tests with holding the breath during inhalation and exhalation, with physical activity (step analysis), thermal testing and diagnosing the reaction of the embryo to ultrasound examination. A change in the CTG curve against the background of functional (non-stress) tests makes it possible to diagnose embryonic hypoxia and its severity. The stress oxytocin test is used infrequently due to possible complications for mother and fetus.
Doppler ultrasound allows you to study blood flow in the aorta and umbilical cord of the embryo and in the uterine arteries, obtaining blood flow velocity curves on the monitor screen. Normally, in the third trimester of gestation there is a gradual increase in volumetric blood flow due to a decrease in peripheral vascular resistance. When the fetoplacental circulation is disrupted, the diastolic blood flow in the umbilical cord artery and the fetal aorta decreases. Decompensated fetoplacental insufficiency has negative and zero diastolic blood flow parameters.
The biophysical profile of the embryo is a cumulative score of 5 parameters: the results of a non-stress test according to CTG data and 4 indicators of ultrasound of the embryo. The respiratory movements of the embryo, motor activity and tone of the embryo, volume amniotic fluid taking into account the degree of “maturity” of the placenta. The score indicates the severity of oxygen deficiency in the embryo.
Ultrasound placentography involves determining the location, size and structure of the placenta. During the normal course of gestation, “maturation” of the placenta occurs and a progressive increase in its thickness and area by the time of delivery. With placental insufficiency, there is a thinning or thickening of the placenta, a decrease or increase in its area, and premature pathological and maturing changes in its structure (cysts, calcification, infarctions and hemorrhages).
Amnion biopsy - examination of amniotic fluid obtained by transabdominal (less often transcervical) biopsy of the amniotic cavity under ultrasound control, allows for a biochemical and cytological examination of the cells of the embryo, determining its sex, chromosomal pathology, metabolic pathologies, malformations (during gestation 16-18 weeks).
For gestation periods greater than 34 weeks, the following is determined:
pH, PCO2, Po2, content of electrolytes, urea, protein in amniotic fluid (to diagnose the severity of embryonic hypoxia;
The level of hormones (lactogen created by the placenta, estriol), enzymes (alkaline phosphatase, β-glucuronidase, hyaluronidase, etc.) (to exclude placental insufficiency and fetal malnutrition);
Optical density of bilirubin, blood group of the embryo, titer of Rh or group antibodies (to diagnose the severity of hemolytic pathology of the embryo);
Biochemical and cytological (creatinine, phospholipids) parameters (to assess the degree of maturity of the embryo).
Biochemical studies of the level of special enzymes (oxytocinase and thermostable alkaline phosphatase) of the placenta in the dynamics of the second and third trimesters of gestation make it possible to identify the functional state of the placenta.
Examination of indicators of the acid-base state (ABS) of the embryo (Pn, PCO2 and Po2) is carried out by cordocentesis (biopsy of the umbilical cord of the embryo during amnion biopsy) during pregnancy or biopsy of the presenting part of the embryo during childbirth (Saling test). It is also possible to use fetal fluid for research. The CBS parameters in comparison with the results of clinical and instrumental studies (CTG, ultrasound) make it possible to objectively establish the severity of oxygen deficiency.
Determination of the level of hormones (progesterone, lactogen created by the placenta, estrogens) formed in the placenta and organs of the embryo is carried out in the second and third trimester of gestation. Normally, the content of all hormones always increases towards the end of gestation. With placental insufficiency, there is a decrease in the level of progesterone and placental lactogen. An indicator of fetal distress is a decrease in the amount of estriol (produced mostly in the embryo). In case of chronic placental insufficiency with impaired trophism of the embryo, a decrease in the concentration of all hormones is detected.
During the physiological course of pregnancy, the condition of the fetus is assessed based on:
The results of comparing the sizes of the uterus and fetus with gestational age;
Auscultation of fetal heart sounds at each visit to a pregnant antenatal clinic:
Fetal motor activity;
The results of ultrasound, which is performed at gestational ages of 18-22 weeks, 32-33 weeks and before birth (to identify the correspondence of the biophysical profile of the fetus and the degree of maturity of the placenta to the gestational age).
In case of a complicated pregnancy, assessment of the condition of the fetus is included in the complex of inpatient examination of the pregnant woman, aimed at diagnosing her pathology, fetal hypoxia and determining the degree of its severity.
To diagnose fetal hypoxia, you need:
Assessment of fetal cardiac activity:
Assessment of fetal motor activity;
Amnioscopy;
Ultrasound of the fetus and placenta.
Fetal cardiac activity is assessed based on the results of auscultation of fetal heart sounds and cardiotocography (CTG). Auscultation of fetal heart sounds is carried out at each examination of the pregnant woman, in the first stage of labor - every 15-30 minutes and outside contractions, in the second stage of labor - after each contraction. The frequency, rhythm and sonority of fetal heart sounds are assessed. Tachy or bradycardia, arrhythmia, dull or muffled fetal heartbeat are clinical signs of hypoxia.
Ante- and intrapartum cardiotocography allows one to assess the fetal heart rate against the background of uterine contractility and fetal motor activity. Changes in basal rate, heart rate variability, acceleration and deceleration reflect the condition of the fetus and may be signs of hypoxia.
Fetal motor activity is assessed by counting the number of fetal movements in 30 minutes in the morning and evening. Normally, 5 or more fetal movements are recorded in 30 minutes. By the evening, in healthy pregnant women, fetal motor activity increases. With the onset of fetal hypoxia, an increase in frequency and intensification of movements are observed; with progressive hypoxia, a weakening and decrease in movements are observed, followed by cessation of fetal movements. With chronic fetal hypoxia, there is an excessive increase or sharp decrease in the difference between the number of movements in the morning and the number of movements in the evening.
The reaction of the fetal heartbeat to its motor activity can be objectively recorded with CTG (myocardial reflex).
Amnioscopy (transcervical examination of the lower pole of the fetal bladder) is performed using an amnioscope in the absence of contraindications (placenta previa, colpitis, endocervicitis) but during pregnancy (after 37 weeks) and in the first stage of labor. Normally, there is a sufficient amount of light, transparent amniotic fluid; with fetal hypoxia, there is a small amount of greenish water and lumps of meconium.
Ultrasound examination makes it possible to identify fetal growth retardation syndrome and fetoplacental insufficiency, on the basis of which chronic intrauterine fetal hypoxia can be established.
To clarify the severity of fetal hypoxia, it is necessary to use:
CTG with functional (stress) tests;
Ultrasound with Doppler sonography;
Determination of the biophysical profile of the fetus, ultrasound placentography;
Amniocentesis;
Biochemical studies of placental enzymes and indicators of acid-base balance of the fetus;
Hormone level studies.
CTG with functional (stress) tests is performed in order to timely identify the compensatory capabilities of the fetus. It is possible to conduct tests with holding the breath while inhaling and exhaling, with physical activity (step test), thermal testing and identifying the fetal reaction to ultrasound examination. A change in the CTG curve against the background of functional (non-stress) tests makes it possible to diagnose fetal hypoxia and its severity. The stress oxytocin test is rarely used due to possible complications for the mother and fetus.
Ultrasound with Dopplerography makes it possible to examine blood flow in the aorta and umbilical cord of the fetus and in the uterine arteries, obtaining blood flow velocity curves on the monitor screen. Normally, in the third trimester of pregnancy, there is a gradual increase in volumetric blood flow due to a decrease in peripheral vascular resistance. When fetoplacental circulation is disrupted, diastolic blood flow in the umbilical cord artery and fetal aorta decreases. Decompensated fetoplacental insufficiency has zero and negative diastolic blood flow indicators.
The biophysical profile of the fetus is a cumulative score of five parameters: the results of a non-stress test according to CTG data and four indicators of fetal ultrasound. The respiratory movements of the fetus, motor activity and tone of the fetus, the volume of amniotic fluid are assessed, taking into account the degree of “maturity” of the placenta. The score indicates the severity of fetal hypoxia.
Ultrasound placentography involves determining the location, size and structure of the placenta. During the normal course of pregnancy, the placenta “maturation” and a progressive increase in its thickness and area occurs by the time of delivery. With placental insufficiency, there is thinning or thickening of the placenta, an increase or decrease in its area, as well as premature ripening And pathological changes its structures (cysts, calcification, infarctions and hemorrhages).
Amniocentesis is a study of amniotic fluid obtained by transabdominal (less commonly, transcervical) puncture of the amniotic cavity under ultrasound control, allowing for cytological and biochemical examination of fetal cells, determining its gender, chromosomal pathology, metabolic diseases, developmental defects (during gestation 16-18 weeks ).
For periods of pregnancy greater than 34 weeks, the following is determined:
pH, pCO2, pO2, content of electrolytes, urea, protein in amniotic fluid (to diagnose the severity of fetal hypoxia;
Level of hormones (placental lactogen, estriol), enzymes (alkaline phosphatase, β-glucuronidase, hyaluronidase, etc.) (to exclude placental insufficiency and fetal malnutrition);
Optical density of bilirubin, fetal blood group, titer of Rh or group antibodies (to diagnose the severity of fetal hemolytic disease);
Cytological and biochemical (creatinine, phospholipids) indicators (to assess the degree of fetal maturity).
Biochemical studies of the level of specific enzymes (oxytocinase and thermostable alkaline phosphatase) of the placenta in the dynamics of the second and third trimesters of pregnancy make it possible to identify the functional state of the placenta.
The study of indicators of the acid-base state (ABS) of the fetus (pH, pCO2 and pO2) is carried out by cordocentesis (puncture of the fetal umbilical cord during amniocentesis) during pregnancy or puncture of the presenting part of the fetus during childbirth (Saling test). Amniotic fluid can also be used for research. The CBS indicators in comparison with the results of clinical and instrumental studies (CTG, ultrasound) make it possible to objectively determine the severity of hypoxia.
Determination of the level of hormones (progesterone, placental lactogen, estrogens) formed in the placenta and fetal organs is carried out in the II and III trimester of pregnancy. Normally, the content of all hormones constantly increases towards the end of pregnancy. With placental insufficiency, there is a decrease in the level of progesterone and placental lactogen. An indicator of fetal suffering is a decrease in the amount of estriol (produced mainly in the fetal body). In case of chronic placental insufficiency with impaired fetal trophism, a decrease in the concentration of all hormones is detected.
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Methods for assessing the condition of the fetus 1. Assessment of the characteristics of the anatomical development of the fetus. 2. Study of its functional state. To assess the condition of the fetus during pregnancy and childbirth, clinical, biochemical and biophysical research methods are used
Clinical methods: auscultation, determination of the frequency of fetal movements, determination of the rate of uterine growth, determination of the nature of coloring of the amniotic fluid (during amnioscopy, amniocentesis, rupture of amniotic fluid)
Amnioscopy n Examination of the lower pole ovum(membrane, amniotic fluid and presenting part of the fetus) using an amnioscope.
n n Normal color of amniotic fluid is transparent or straw-yellow Pathological coloring: Green – stained with meconium, a sign of fetal hypoxia Bright yellow (golden) – Rhesus conflict Red – premature placental abruption Brown (dark brown)– fetal death fetus
Amniocentesis Puncture of the amniotic membrane to obtain amniotic fluid for subsequent laboratory research, or the introduction of drugs into the amniotic cavity.
Biochemical methods for studying the hormonal profile: human chorionic gonadotropin, placental lactogen, estrogens (estriol), progesterone, prolactin, thyroid hormones, corticosteroids; determination of the degree of fetal maturity based on cytological examination of amniotic fluid and the concentration of phospholipids (lycetin and sphingomyelin) in amniotic fluid obtained by amniocentesis; examination of fetal blood obtained by intrauterine puncture - cordocentesis; chorionic villus biopsy for fetal karyotyping and detection of chromosomal and gene abnormalities.
Electrocardiography determines heart rate, rhythm pattern, size, shape and duration of the ventricular complex. Phonocardiography is represented by oscillations reflecting the 1st and 2nd heart sounds.
Echography (ultrasound) n n n Carrying out dynamic fetometry Assessing the general and respiratory movements of the fetus Assessing the fetal cardiac activity Measuring the thickness and area of the placenta Determining the volume of amniotic fluid Measuring the speed of fetal-uterine circulation (Doppler)
Cardiotocography (CTG) is a continuous synchronous recording of the fetal heart rate (HR) and uterine tone with a graphical representation of the signals on a calibration tape.
Heart rate registration is carried out by an ultrasonic sensor based on the Doppler effect. Registration of uterine tone is carried out by strain gauges.
CTG parameters n n n basal level of heart rate variability of the basal rhythm: frequency and amplitude of oscillations amplitude and duration of accelerations and decelerations fetal heart rate in response to contractions fetal movements functional tests
The basal rhythm is a long-term change in heart rate of 160 beats. 10 min. 120 beats Physiological basal rhythm – 120 -160 beats. /min. During pregnancy – 140 -150 beats. /min. The first stage of labor is 140 -145 beats. /min. Second stage of labor – 134 -137 beats. /min.
Amplitude 145 max min 135 1 min. The amplitude, or width of the recording, is calculated between the maximum and minimum deviations in heart rate within 1 minute.
Based on amplitude, the following types of oscillations are distinguished n n “silent” or monotonic type – deviations from the basal level are 5 or less beats per minute “slightly undulating” – 5-9 beats/min “undulating” (uneven, intermittent) type – deviations from the basal level 10 -25 beats/min “saltatory” (jumping) type – deviations from the basal level more than 25 beats/min).
Classification of oscillations 140 0 -5 beats. /min 100 140 “Mute” type 5 -9 beats. /min Slightly undulating type
140 10 -25 beats /min. Undulating type 180 140 100 25 and beat. /min. Saltator type
The frequency of oscillations is determined by the number of intersections of a line drawn through the middle of the oscillations in 1 minute 160 139 1 minute. Low – less than 3 oscillations per minute Moderate – from 3 to 6 oscillations per minute High – more than 6 oscillations per minute
ACCELERATION 160 DECELERATION 120 Acceleration – increase in heart rate by 15 beats/min for at least 15 seconds. Deceleration – slowing down the heart rate by 15 beats/min for 10 seconds. and more
Criteria for normal. GCT n n Basal rhythm within 120 -160 beats/min Amplitude of basal rhythm variability - 5 -25 beats/min Frequency of oscillations 6 or more per minute Decelerations are absent or sporadic, shallow and very short 2 accelerations or more are recorded during 10 minutes of recording
n n n 8 - 10 points is the norm. 6-7 points – pre-pathological type, re-examination is necessary. Less than 6 points – pathological type, signs of intrauterine fetal hypoxia, requires immediate hospitalization or urgent delivery.
The widespread introduction into clinical practice of various methods for assessing the condition of the fetus contributes to a significant reduction in perinatal mortality, which is one of the main indicators of the level of development medical care. Diagnostics is carried out in two directions: 1 – assessment of the characteristics of the anatomical development of the fetus, 2 – study of its functional state.
To assess the condition of the fetus during pregnancy and childbirth, clinical, biochemical and biophysical research methods are used.
TO clinical methods diagnostics relate:
· auscultation,
· determination of fetal movement frequency,
Determination of the growth rate of the uterus,
· determination of the nature of staining of amniotic fluid (during amnioscopy, amniocentesis, rupture of amniotic fluid).
Widely used in obstetrician's daily practice auscultation method using a stethoscope , the rhythm and frequency of heart contractions, the clarity of heart sounds are assessed. Normally, the fetal heart rate ranges from 120 to 160 beats per minute. However, auscultation of the fetal heartbeat is not always useful for assessing the condition of the fetus or diagnosing fetal hypoxia. It allows you to detect only gross changes in heart rate (HR) - tachycardia, bradycardia and severe arrhythmia, which occur more often during acute hypoxia. With chronic hypoxia, in most cases it is not possible to detect changes in cardiac activity by auscultation. Auscultation of the fetal heart rate is of great value in determining fetal well-being if it is used as a test to assess fetal responsiveness. For this purpose, the fetal heartbeat is listened to before and after its movements. Increased fetal heart rate in response to movement is a clear indicator of good fetal health. The absence of a heart rate response or the appearance of only a slight increase in heart rate may indicate fetal hypoxia and requires additional research methods.
An indicator of the condition of the fetus is its motor activity , which in healthy pregnant women reaches a maximum at 32 weeks, after which the number of fetal movements decreases. The appearance of fetal movements (MF) indicates its good condition. If the mother feels DP without their reduction or decrease in activity, then the fetus is healthy and there is no threat to its condition. Conversely, if the mother notes a certain decrease in DP, then he may be in danger. At initial stages intrauterine fetal hypoxia, restless fetal behavior is observed, which is expressed in increased frequency and intensification of its activity. With progressive hypoxia, weakening and cessation of movements occurs.
To assess the motor activity of the fetus, special forms are offered in which the pregnant woman marks each DP from 9:00 to 21:00, that is, 12 hours in advance . Number of DP more than 10 indicates a satisfactory condition of the fetus. If a woman notes less than 10 movements, especially two days in a row, then this condition is regarded as threatening to the fetus. Consequently, the obstetrician receives information about the intrauterine state of the fetus from the pregnant woman herself. The registration method does not deprive women of their daily normal activities. Upon receipt negative results The doctor should refer the pregnant woman to a hospital for examination.
In inpatient conditions, in addition to additional research methods, it is possible to use a second method of recording DP to assess its intrauterine state. Pregnant DP is recorded lying on the side for 30 minutes. four times a day (9:00, 12:00, 16:00 and 20:00) and entered into special cards. When assessing the results, it is important to pay attention not only to a certain number of movements (if the condition of the fetus is satisfactory, it should be at least 4 in 2 hours), but also to change their number over several days. Fetal suffering is indicated by: complete disappearance of motor activity or a decrease in the number of fetal movements by 50% per day. If in next days DP returns to its previous level, then there is no danger to the fetus at the moment.
Of particular value in the diagnosis of fetal hypoxia is the combined registration of its cardiac activity and motor activity.
A significant amount of information about the condition of the fetus can be obtained by measuring the height of the uterine fundus. These measurements are usually used between 20 and 36 weeks pregnancy. To determine the rate of growth and development of the fetus it is necessary over time (every 2 weeks) measure the height of the uterine fundus above the symphysis pubis and abdominal circumference. Comparison of the obtained sizes with the gestational age allows us to identify retardation in fetal growth. Lag fundal height of the uterus on 2 cm and more compared to the norm or lack of growth for 2–3 weeks . during dynamic monitoring of a pregnant woman indicates fetal growth restriction , which requires further evaluation. There are many factors that make it difficult to assess fetal growth (violation of measurement techniques, disorders of fat metabolism in the mother, excess or reduced amount of amniotic fluid, multiple pregnancy, incorrect position and fetal presentation). However, fundal height measurements remain a good clinical indicator of normal, accelerated or reduced fetal growth.
Amniotic fluid staining during pregnancy can be detected by amnioscopy or amniocentesis, as well as in case of premature rupture of membranes.
Amnioscopy– transcervical examination of the lower pole of the amniotic sac. Availability meconium impurities indicates chronic fetal hypoxia or former acute short-term hypoxia, and the fetus, in the absence of new disturbances in its oxygen supply, can be born without asphyxia. The presence of a small admixture of meconium in the amniotic fluid (yellow or greenish color) with premature pregnancy is not an absolute sign of fetal hypoxia. If the meconium in the amniotic fluid is in large quantities(dark green or black color) especially in high-risk pregnant women (late gestosis, Rh isoimmunization, chorioamnionitis, etc.), this is regarded as a threatening condition of the fetus. Cloudy staining amniotic fluid indicates post-term pregnancy, yellow – about HDP or Rhesus incompatibility.
Biochemical methods for diagnosing the condition of the fetus:
· study of the hormonal profile: human chorionic gonadotropin, placental lactogen, estrogens (estriol), progesterone, prolactin, thyroid hormones, corticosteroids;
· determination of the degree of fetal maturity based on cytological examination of amniotic fluid and the concentration of phospholipids (lycetin and sphingomyelin) in amniotic fluid obtained by amniocentesis;
· examination of fetal blood obtained by intrauterine puncture - cordocentesis;
· chorionic villus biopsy for fetal karyotyping and determination of chromosomal and gene abnormalities.
To assess the condition of the fetus during pregnancy, they also examine hormonal activity of the fetoplacental system , which to a certain extent depends on the physiological activity of the fetus and to a large extent on functional activity placenta. Among biochemical methods Research has found the most widespread application in practice in determining the concentration of estriol and placental lactogen in the mother’s body.
In non-pregnant women estriol is the main metabolite of the main estrogen - estradiol. During pregnancy, the fetus and placenta are responsible for most estriol production. The average daily amount of hormone excreted in urine is 30-40mg. Selection less than 12 mg/day indicates a decrease in the activity of the fetoplacental complex. Reducing estriol content up to 5 mg/day indicates fetal distress. Decrease in estriol excretion below 5 mg/day threatens the life of the fetus. Since the level of estriol in the mother’s body is influenced by many factors (the state of liver and kidney function, the difficulty of collecting daily urine, taking medications, a wide range of test results, etc.), the information obtained when determining the level of estriol is valuable if it coincides with other clinical and biophysical indicators. It is generally accepted that estriol levels reliably reflect fetal health in complicated pregnancies. late gestosis, growth retardation of the mother of the fetus, diabetes mellitus mothers, that is, in the group of pregnant women at high risk of fetal hypoxia.
Placental lactogen (PL) synthesized by the placenta and can be determined in maternal serum. The concentration of PL in the mother's blood is directly dependent on the mass of the functioning placenta. Consequently, during normal pregnancy, serum PL values increase as the placenta grows. In the presence of a pathologically small placenta, PL levels in maternal blood are low. Determination of PL can play a significant role in assessing the condition of the fetus in women who have a fibrous placenta with small infarcts, especially when pregnancy is complicated by late gestosis or in the presence intrauterine retention fetal growth. During a physiologically proceeding pregnancy, the content of PL in the mother’s blood gradually increases and in a full-term pregnancy is from 6 to 15 μg/ml, then a decrease in PL in women after 30 weeks. pregnancy to the level less than 4 µg/ml is dangerous for the fetus. A few weeks before the death of the fetus, the level of PL drops sharply. With insufficient placental functions, a moderate decrease in the level of PL in the blood is observed. The results of determining the PL content obviously cannot be used as the only criterion for diagnosing fetal hypoxia.
However, in modern clinical practice, determining the level of estriol in the blood and its excretion in urine is not widely used, especially since the determination of estriol gives about 80% of false positive results. The determination of the level of placental lactogen is of the same low importance. Currently, they have been replaced by methods of ultrasound examination and electronic monitoring of the fetus.
The most informative are considered biophysical methods for assessing the condition of the fetus . These include: electro- and phonocardiography, echography and cardiotocography, which are widely used in the daily work of an obstetrician.
Methods for studying fetal cardiac activity are also indirect (from the abdominal wall of the uterus) electrocardiography and phonography of the fetus. When analyzing antenatal ECG is determined Heart rate, rhythm pattern, size, shape and duration of the ventricular complex. With fetal hypoxia, cardiac conduction disturbances, changes in the amplitude and increase in the duration of heart sounds, and their splitting are detected. The occurrence of murmurs, especially systolic ones, during chronic fetal hypoxia indicates a serious fetal condition.
FKG presented oscillations reflecting the 1st and 2nd heart sounds. Umbilical cord pathology is characterized by the appearance of systolic murmur on PCG and uneven amplitude of heart sounds.
Ultrasonography is the most reliable and accurate method of antenatal diagnosis of the fetal condition.
The method allows:
· carry out dynamic fetometry,
Assess general and respiratory movements of the fetus,
Fetal cardiac activity
thickness and area of the placenta,
volume of amniotic fluid,
· measure the rate of fetal-uterine circulation.
First of all, determine biparietal size of the fetal head (BFR), average diameters chest(DG) and abdomen (J). A reliable sign of fetal growth restriction is a discrepancy of 2 weeks. and more BDP of the fetal head to the actual period of pregnancy, as well as a violation of the relationship between the sizes of the head and body of the fetus. Comprehensive ultrasound assessment of fetal growth rates allows early diagnosis and an objective assessment of the fetal condition.
Of great importance study of fetal respiratory movements. To analyze the fetal respiratory activity, the following indicators are used: index of fetal respiratory movements (percentage ratio of the time of respiratory movements to the total duration of the study); frequency of fetal respiratory movements (number of respiratory movements per minute); average duration of episodes of respiratory movements; average number of respiratory movements per episode. The duration of the study should be at least 30 minutes. If there are no fetal respiratory movements, the study is repeated the next day. The absence of respiratory movements within 2-3 studies is regarded as a poor prognostic sign. Signs of fetal distress are changes in the nature of respiratory activity in the form of a sharp decrease or increase. With severe fetal hypoxia, the nature of fetal movements changes. Respiratory movements appear in the form of hiccups or intermittent breathing with prolonged episodes of apnea.
The most accessible, reliable and accurate method for assessing the condition of the fetus during the last trimester of pregnancy is Cardiotocography (CTG) of the fetus. The cardiotocograph is designed in such a way that it simultaneously records fetal heart rate, uterine contractions and fetal movements. Modern cardiotocographs meet all the requirements for monitoring the fetal heartbeat and contractile activity of the uterus both during pregnancy and during childbirth. Currently, it is generally accepted to carry out screening monitoring of the condition of the fetus, both in outpatient setting, and in the hospital. In groups at risk for perinatal losses, screening control is carried out over time. Typically, fetal heart rate recording is used from 30 weeks. pregnancy on a belt moving at a speed of 10 to 30 mm/min for 30 minutes.
To characterize the condition of the fetus using CTG, the following indicators are used: basal heart rate level, basal rhythm variability, frequency and amplitude of oscillations, amplitude and duration of accelerations and decelerations, fetal heart rate in response to contractions, fetal movements and functional tests.
Under basal rhythm (BR) understand long-term changes in heart rate. A decrease below 120 beats/min is classified as bradycardia, and an increase above 160 beats/min is classified as tachycardia. Therefore, a long-term heart rate in the range of 120-160 beats/min is regarded as the normal range. Tachycardia is classified according to severity: mild (160-170 beats/min) and severe (more than 170 beats/min). Bradycardia is also divided into mild (120-100 beats/min) and severe (less than 100 beats/min) severity. If bradycardia occurs within a period of no more than 3 minutes, and then it returns to the original BR, then it is called deceleration.
1. Clinical:
A) auscultation using an obstetric stethoscope– the rhythm and frequency of heart contractions, the clarity of heart sounds are assessed. Acuscultation allows us to detect only gross changes in heart rate - tachycardia, bradycardia and severe arrhythmia, which occur more often during acute hypoxia. With chronic hypoxia, in most cases it is not possible to detect changes in cardiac activity by auscultation. Auscultation of the fetal heart rate is of great value in determining fetal status if used As a test forEstimates of its reactivity. For this purpose, the fetal heartbeat is listened to before and after its movements. Increased fetal heart rate in response to movement is a clear indicator of good fetal health. The absence of a heart rate response or the appearance of only a slight increase in heart rate may indicate fetal hypoxia and requires additional research methods.
B) study of fetal motor activity– in healthy pregnant women it reaches a maximum at 32 weeks, after which the number of fetal movements decreases. The appearance of fetal movements (MF) indicates its good condition. If the mother feels DP without their reduction or decrease in activity, then the fetus is healthy and there is no threat to its condition. Conversely, if the mother notes a certain decrease in DP, then he may be in danger. In the initial stages of intrauterine fetal hypoxia, restless fetal behavior is observed, which is expressed in increased frequency and intensification of its activity. With progressive hypoxia, weakening and cessation of movements occurs. To assess the motor activity of the fetus, special forms are offered in which the pregnant woman Marks each DP from 9 a.m. to 9 p.m., that is, 12 hours in advance. The number of DP more than 10 indicates a satisfactory condition of the fetus. If a woman notices less than 10 movements, especially two days in a row, then this condition is regarded as threatening to the fetus. Consequently, the obstetrician receives information about the intrauterine state of the fetus from the pregnant woman herself. The registration method does not deprive women of their daily normal activities. If negative results are obtained, the doctor should refer the pregnant woman to a hospital for examination.
In inpatient conditions, in addition to additional research methods, it is possible to use a second method of recording DP to assess its intrauterine state. Pregnant DP is recorded lying on its side in For 30 minutes, four times a day (9.00, 12.00, 16.00 and 20.00) And they put it on special cards. When assessing the results, it is important to pay attention not only to a certain number of movements (if the fetus is in satisfactory condition, it should be at least 4 in 2 hours), but also to the change in their number over several days. Fetal suffering is indicated; complete disappearance of motor activity or a decrease in the number of DPs by 50% per day. If in the following days the DP returns to its previous level, then there is currently no danger to the fetus.
Of particular value in the diagnosis of fetal hypoxia is the combined registration of its cardiac activity and motor activity.
C) determining the growth rate of the uterus– to determine the rate of growth and development of the fetus, it is necessary to dynamically (every 2 weeks) measure the height of the uterine fundus above the symphysis pubis and the circumference of the abdomen. Comparison of the obtained dimensions with the gestational age allows us to identify retardation in fetal growth. A lag in the height of the uterine fundus by 2 cm or more compared to the norm or the absence of its increase within 2-3 weeks. during dynamic monitoring of a pregnant woman, this indicates fetal growth retardation, which requires further evaluation. There are many factors that make it difficult to assess fetal growth (violation of measurement techniques, disorders of fat metabolism in the mother, excess or reduced amount of amniotic fluid, multiple pregnancies, incorrect position and presentation of the fetus). However, fundal height measurements remain a good clinical indicator of normal, accelerated or reduced fetal growth.
D) staining of amniotic fluid– during pregnancy can be detected by amnioscopy or amniocentesis, as well as with premature rupture of membranes. Amnioscopy is a transcervical examination of the lower pole of the amniotic sac. The presence of meconium impurities indicates chronic fetal hypoxia or former acute short-term hypoxia, and the fetus, in the absence of new disturbances in its oxygen supply, can be born without asphyxia. The presence of a small admixture of meconium in the amniotic fluid (yellow or greenish color) during premature pregnancy is not an absolute sign of fetal hypoxia. If meconium in the amniotic fluid is in large quantities (dark green or black), especially in high-risk pregnant women (late gestosis, Rh isoimmunization, chorioamniomitis, etc.), then this is regarded as a threatening condition of the fetus. Turbid coloring of the amniotic fluid indicates a post-term pregnancy, yellow coloration indicates about. HDP or Rh incompatibility.
2. Biochemical - research Hormonal activity of the fetoplacental system , Which depends on the physiological activity of the fetus and, to a large extent, on the functional activity of the placenta.
A) determination of estriol in blood and urine– in non-pregnant women, estriol is the main metabolite of the main estrogen – estradiol. During pregnancy, the fetus and placenta are responsible for most estriol production. The average daily amount of hormone excreted in urine is 30-40 mg. Selection Less than 12 mg/day Indicates a decrease in the activity of the fetoplacental complex. Reducing estriol content Up to 5 mg/day indicates fetal distress. Decrease in estriol excretion Below 5 mg/day threatens the life of the fetus. Since the level of estriol in the mother’s body is influenced by many factors (the state of liver and kidney function, the difficulty of collecting daily urine, taking medications, a wide range of test results, etc.), the information obtained when determining the level of estriol is valuable if it coincides with other clinical and biophysical indicators. It is generally accepted that estriol levels reliably reflect the condition of the fetus in the case of pregnancy complicated by late gestosis, fetal growth retardation, maternal diabetes, that is, in a group of pregnant women at high risk of fetal hypoxia.
B) determination of placental lactogen (PL) in the blood– PL is synthesized by the placenta, its concentration in the mother’s blood is directly dependent on the mass of the functioning placenta. During normal pregnancy, serum PL values increase as the placenta grows. In the presence of a pathologically small placenta, PL levels in maternal blood are low. Determining PL can play a significant role in assessing the condition of the fetus in women who have a fibrous placenta with small infarcts, especially when pregnancy is complicated by late gestosis or in the presence of intrauterine growth retardation. During a physiologically proceeding pregnancy, the content of PL in the mother’s blood gradually increases and in a full-term pregnancy is From 6 to 15 µg/ml, decrease in PL in women after 30 weeks. pregnancy to the level Less than 4 µg/ml is dangerous for the fetus. A few weeks before the death of the fetus, the level of PL drops sharply. With insufficient placental functions, a moderate decrease in the level of PL in the blood is observed.
3. Biophysical– the most informative:
A) echography (ultrasound)– the most reliable and accurate method of antenatal diagnosis of the fetal condition. Allows for dynamic photometry, assessment of general and respiratory movements of the fetus, fetal cardiac activity, thickness and area of the placenta, volume of amniotic fluid, and measurement of the rate of fetal-uterine circulation. Define b Iparietal size of the fetal sister-in-law (FSD),Average diameters of the chest (DH) and abdomen (AD). A reliable sign of fetal growth restriction is a discrepancy of 2 weeks. and more BDP of the fetal head to the actual gestational age, as well as a violation of the relationship between the sizes of the head and body of the fetus. A comprehensive ultrasound assessment of fetal growth rates allows for early diagnosis and objective assessment of the fetal condition. Of great importance Study of fetal respiratory movements . To analyze the respiratory activity of the fetus, the following indicators are used: 1) index of fetal respiratory movements (percentage ratio of the time of respiratory movements to the total duration of the study), 2) frequency of fetal respiratory movements (number of respiratory movements per minute); 3) the average duration of episodes of respiratory movements; 4) the average number of respiratory movements per episode. The duration of the study should be At least 30 minutes. If there are no fetal respiratory movements, the study is repeated the next day. Lack of breathingMovements during 2-3 studies are regarded as a poor prognostic sign. Signs of fetal distress are changes in the nature of respiratory activity in the form of a sharp decrease or increase. With severe fetal hypoxia, the nature of fetal movements also changes. Respiratory movements appear in the form of hiccups or intermittent breathing with prolonged episodes of apnea.
B) indirect (from the abdominal wall of the uterus) electrocardiography and phonography of the fetus – When analyzing an antenatal ECG, heart rate, rhythm pattern, size, shape and duration of the ventricular complex are determined. With fetal hypoxia, cardiac conduction disturbances, changes in the amplitude and increase in the duration of heart sounds, and their splitting are detected. The occurrence of murmurs, especially systolic ones, during chronic fetal hypoxia indicates a serious fetal condition. The PCG is represented by oscillations reflecting the 1st and 2nd heart sounds. Umbilical cord pathology is characterized by the appearance of systolic murmur on PCG and uneven amplitude of heart sounds.
B) cardiotocography (CTG)– the most accessible, reliable and accurate method for assessing the condition of the fetus during the last trimester of pregnancy . The cardiotocograph simultaneously records fetal heart rate, uterine contractions and fetal movement. Currently, it is generally accepted to carry out screening monitoring of the condition of the fetus both on an outpatient basis and in a hospital. In groups at risk for perinatal losses, screening control is carried out over time. Typically, fetal heart rate recording is used from 30 weeks. pregnancy on a tape moving at a speed of 10 to 30 mm/min, for at least 30 minutes.
To characterize the condition of the fetus using CTG, useThe following indicators: basal heart rate level, basal rhythm variability, frequency and amplitude of oscillations, amplitude and duration of accelerations and decelerations, fetal heart rate in response to contractions, fetal movements and functional tests.
Criteria Normal CTT:
■ Basal rhythm within 120-160 beats/min;
■ Amplitude of basal rhythm variability – 5-25 beats/min;
■ There is no deceleration or there are sporadic, shallow and very short decelerations;
■ 2 or more accelerations are recorded during 10 minutes of recording.
Despite the fact that CTG is a fairly informative method that allows you to determine the condition intrauterine fetus, the information content of the research increases significantly if they are combined with Functional tests:
1) non-stress test to determine fetal reactivity– CTG recording is carried out for 20 minutes. If during this time at least 2 accelerations of 15 or more beats/min with a duration of 15 s or more in combination with fetal movements were detected, then this indicates a favorable (reactive) state of the fetus. Currently, many NT are stopped after 10 minutes if two accelerations are observed. If fetal movements do not appear within 20 minutes, it is necessary to stimulate fetal movements by palpation of the uterus and extend the observation time to 40 minutes. The appearance after this of fetal movement and corresponding acceleration determines the reactivity of the test. If fetal movements do not appear spontaneously or after external influences or if there is no acceleration of heart rate in response to fetal movements, the test is considered non-reactive or non-reactive. The reactivity of the fetus is usually due to its intrauterine suffering. A non-stress test is recommended to be carried out from the 30th week of pregnancy once every 2-4 weeks
2) contractile stress test (oxytocin)– the only form of stress on the fetoplacental system in clinical practice is uterine contraction. A normal healthy fetus tolerates uterine contractions without any difficulty, as evidenced by the absence of periodic changes in heart rate. With hypoxia, the fetus is often unable to tolerate the insufficient supply of oxygen observed during uterine contractions, which affects its cardiac activity. To perform a contractile stress test, uterine contractions are stimulated with intravenous oxytocin. . A CTG device is placed on the abdominal wall and the activity of the uterus and heart rate are monitored for 15-20 minutes. Many women who undergo OT in conjunction with a nonreactive nonstress test may experience normal fetal movements during this period and do not require oxytocin stimulation. Other women experience spontaneous uterine contractions of sufficient frequency and duration that also do not require the use of oxytocin. In many pregnant women, uterine contractions can be induced by gently massaging the nipples with a warm towel. Inducing contractions by mechanical stimulation of the nipples is the simplest form of contractile stress test. It succeeds in most cases. Only in case of a negative effect from nipple stimulation, FROM load is applied as the last step. The sensitivity of the myometrium to oxytocin varies and is undetectable before the test. Therefore, intravenous administration of oxytocin should be started with small doses - 0.05 IU (1 ml of synthetic oxytocin - 5 IU - in 100 ml of 5% glucose solution) or 0.01 IU. The rate of administration is at least 1 ml/min, doubled every 5-10 minutes until three uterine contractions lasting 40-60 seconds occur over a 10-minute period. If late decelerations appear before the specified duration and frequency of contractions are achieved, the administration of oxytocin is stopped. The administration of oxytocin is also stopped when uterine contractions become sufficiently frequent (3 in 10 minutes), and the CGG recording is continued until the intervals between contractions become more than 10 minutes. A test with normal heart rate variability without deceleration is considered negative. A questionable test is accompanied by an increase in the basal rhythm above 150 per 1 min or a decrease below 110 per 1 min; a decrease in variability up to the monotony of the rhythm; the occurrence of deceleration in half of the cases of uterine contractions. At positive test Each contraction of the uterus is accompanied by the appearance of late decelerations. With increased activity of the uterus, beta mimetics (alupent, partusisten) are administered intravenously to inhibit its contractions. The clinical use of OT is limited because it is time-consuming and can cause a number of undesirable complications.
D) ultrasound placentography– determine the correspondence of the degree of maturity of the placenta to the gestational age and some of its pathological changes.
D) Doppler study of blood flow in the mother-placenta-fetus system– for each vessel there are characteristic blood flow velocity curves. Blood flow in the uterine artery, umbilical cord artery, and fetal aorta is examined.
Biophysical profile of the fetus– includes the results of a non-stress test conducted during a cardiac monitoring study, and echoscopic indicators determined by ultrasound scanning in real time (fetal respiratory movements, fetal motor activity, fetal tone, volume of amniotic fluid, degree of placental maturity). Each parameter is scored from 0 to 2 points.
Invasive diagnostic methods fetal conditions are used only if the benefit from the information obtained outweighs the possible risk of complications associated with these methods:
A) Amtniocentesis– transabdominal, transvaginal, transcervical – with analysis of amniotic fluid.
B) cordocentesis– obtaining umbilical cord blood by intrauterine puncture under ultrasound control,
IN) Fetoscopy– direct examination of the fetus through a thin endoscope inserted into the amniotic fluid, for the purpose of collecting blood and epidermal samples for genetic research if a congenital anomaly of the fetus is suspected,
G) Chorionic villus sampling– transcervical or transabdominal sampling within 8-12 weeks. under ultrasound control - for fetal karyotyping and determination of chromosomal and gene abnormalities.
