The value of comprehensive fetal assessment in labor

In high-risk women giving birth, it is necessary to perform a comprehensive assessment of the condition of the fetus using cardiotocography, amnioscopy, determination of the nature of labor using external and internal hysterography, determination of the acid-base balance of the fetus and the woman in labor, and determination of the pH of the amniotic fluid.

In this case, amnioscopy and registration of fetal cardiac activity are performed to establish a preliminary diagnosis, and determination of the pH of the blood from the presenting part of the fetus and the pH of the amniotic fluid is for an accurate differential diagnosis. Szanto, Baiflai, Kovacs (1993) believe that determination of the pH of the blood of the fetus and the newborn opens up new possibilities in obstetric practice. During labor, monitoring the pH of the fetal blood helps prevent complications. After labor, determination of the pH of the fetal blood allows early diagnosis of fetal acidosis and timely initiation of intensive treatment.

All methods of assessing the condition of the fetus, with the exception of pH-metry of amniotic fluid and cardiotocography, are reliable over a short period of time, for example, the Saling test does not exceed 30 minutes, i.e. there is no possibility of a long-term prognosis.

Justification of the concept of complex (intensive) observation during labor. Labor is a great burden for both the mother and the fetus, even if the process is physiological. When labor occurs in women from high-risk groups, whose fetus is in a dangerous condition, intensive observation becomes even more important, since there may be a prognostically unfavorable effect of labor on the fetus. Therefore, early diagnosis of dangerous conditions of the fetus is necessary. Along with intensive monitoring of the fetus, it is necessary to decide on the choice of the method of delivery in order to complete labor as carefully and quickly as possible.

At present, it seems obvious that classical observation methods (auscultation of the fetus with an obstetric stethoscope, monitoring for the appearance of meconium in the amniotic fluid, determining the birth tumor, etc.) are insufficient to accurately reflect the condition of the fetus during labor.

It should be noted that blood can be taken from the skin of the fetal head during labor not only to determine the main parameters of the acid-base balance, but also for analyses performed using other microstructural methods:

• if fetal anemia is suspected, a study of hematocrit, hemoglobin, and the number of red blood cells is performed;
• in case of fetal damage due to Rh factor incompatibility, the fetal blood group is determined and a direct Coombs reaction is performed;
• If the mother has diabetes, the blood sugar level of the fetus is determined.

In determining the condition of the fetus during labor, the results of a blood test taken from the skin of the fetus's head are of decisive importance. Acidosis can be recognized at any stage of labor based on the results of a blood test from the skin of the fetus's head.

In case of complex monitoring, which includes hardware methods, a certain technical equipment of the maternity ward and appropriate training of doctors and midwives are required to decipher the data of cardiograms, take blood from the skin of the head (Zaling test), determine the pH of amniotic fluid, etc.

Intensive observation should be mainly carried out in high-risk women in labor, i.e. in complicated pregnancy, extragenital diseases, especially diabetes mellitus, presence of meconium in the amniotic fluid, older primiparous women, abnormal labor, pathological KIT curves. Particular attention should be paid to pregnant women and women in labor in case of early termination of pregnancy in the interests of the fetus, since already in the case of a threatening situation for the fetus it is necessary to induce labor, often with rupture of the amniotic sac, administration of oxytotic agents, which in themselves can worsen the condition of the fetus. Therefore, correct determination of the degree of fetal hypoxia allows choosing the most rational way of labor management.

The following comprehensive approach is used to assess the condition of the fetus and decide on the most rational tactics for managing labor:

1. When a woman in labor who belongs to a high-risk group is admitted, cardiotocography is performed to detect signs of fetal dysfunction.
2. Amnioscopy or visual assessment of the color of the amniotic fluid is performed. In this case, we consider it important to perform after cardiotocography, since the introduction of mirrors or a tube can temporarily change the nature of the fetal cardiac activity. If meconium is present in the amniotic fluid, the fetal bladder is opened to perform the next, third, stage of determining the fetal blood acid-base balance. If the water is clear and the cardiotocography data reflect minor disturbances in the fetus's vital activity, then the fetal bladder is not opened.
3. Next, the fetal blood acid-base balance is determined - the Zaling test, and if the indicators do not require urgent delivery, the fourth stage is carried out - determining the pH of the amniotic fluid.
4. The Express device sensor is inserted behind the fetus's head and, if the pH monitoring of the amniotic fluid is favorable, conservative labor management is continued with continuous calculation of intra-hourly fluctuations in the pH of the amniotic fluid. If acidosis increases according to the pH monitoring data or intra-hourly fluctuations worsen, the Zaling test is repeated.

An integrated approach to diagnosing the condition of the fetus allows for reliable diagnosis of early signs of hypoxia, monitoring the condition of the fetus during labor, promptly treating hypoxia, determining indications for surgical delivery, and contributing to the birth of a healthy child.

Fetal sex as a risk factor. A method for determining fetal sex during labor has been developed. The following circumstances served as the basis for developing this method. Fetal sex as a genetic factor influencing perinatal mortality has not been systematically studied to date. Therefore, it is necessary to clarify the following points:

• to assess the impact of fetal sex on mortality in the perinatal period;
• develop adequate cytogenetic methods for determining the sex of the fetus during childbirth;
• to determine the sex of the fetus in clinical conditions during various complications of pregnancy and childbirth and to clarify its role in choosing the method of delivery.

Mathematical analysis of 11.5 thousand perinatally deceased children showed that antenatal fetal death does not depend on gender, but already intranatally and in the first 6 days of life, an increasing correlation between mortality and gender is observed, reaching 15%. The correlation between mortality and gender is observed regardless of the mass of perinatally deceased children. The proportion of deceased boys increases significantly only during childbirth and in the postnatal period.

A method suitable for clinical conditions has been developed for determining the sex of the fetus based on the content of X- and Y-chromatin in the cells of the amniotic membrane tissue. The study of X- and Y-chromatin was carried out in the nuclei of cells of native preparations of amniotic fluid. Based on the analysis of the content of X- and Y-chromatin in the cells of the amniotic membranes, the sex of the fetus was determined correctly in 97.4% of cases, and in 90% of cases when examining amniotic fluid.

All cases of incorrect determination of fetal sex concerned pregnancies with male fetuses and were characterized by the absence or underestimated values of Y-chromatin with X-chromatin values corresponding to the female sex. Thus, the proposed method for studying amniotic membranes allows for a high degree of accuracy in determining the sex of the fetus during labor. Male fetuses are less resistant to the stress factors of labor.

Thus, intranatal determination of fetal sex using microbiopsies of amniotic membrane tissue and subsequent microscopic examination of both X- and Y-chromatin made it possible to correctly establish sex in 97% of cases.