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Cardiotocography, auscultation of cardiac activity, amniotic fluid staining
Last reviewed: 04.07.2025
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During normal labor, with a physiological state of the fetus, there is a gradual increase in the frequency of the presence of meconium in the amniotic fluid, but no significant differences were found between the groups.
Auscultation of fetal heart activity with an obstetric stethoscope was performed for each woman in labor during labor at least once an hour in the first stage and after each pushing in the second stage of labor. The results of determining the auscultatory fetal heart rate during physiological labor indicate the stability of the studied parameter, and even in the second stage, the average fetal heart rate does not significantly differ from the unambiguous indicators in other groups. Auscultatory fetal heart rate was in the 1st group - (135.1 ± 0.31) beats / min; in the 2nd - (135.9 ± 0.45); in the 3rd - (135.3 ± 0.67); in the 4th - (137.7 ± 0.53); in the 5th - (137.2 ± 0.83); in the 6th group - (136.9 ± 0.4) beats/min.
Cardiotocography, being a safe and accessible method, has found wide application in obstetric practice for diagnosing the condition of the fetus and in this study was performed on all women in labor at least 3 times during the labor process.
The results of cardiotocography show that during physiological labor the average heart rate is within the normal range and practically does not differ from the auscultation data. Changes in heart rate during the first stage of labor do not significantly differ between the groups.
The indicator of the decrease in intra-minute fluctuations during the process of opening of the uterine os gradually increases, although no reliable differences between the groups were revealed during the mathematical analysis, a tendency for the indicator to increase is observed. Similar changes occur with the indicator of the myocardial reflex. At the same time, the indicators of the myocardial reflex and deceleration less often indicate fetal suffering in the absence of hypoxia than intra-minute fluctuations. The increase in the number of decelerations in the 4th group reliably differs from the data of the 3rd group. Between the 2nd and 3rd groups, no reliable differences were revealed.
Thus, despite the physiological state of the fetus, CTG data in a number of cases indicated its intrauterine suffering. Obviously, we should agree with L. Lampe, who believes that changes in cardiac activity belong to the group of functional signs of asphyxia and an assessment of the fetus's condition based only on them is possible only under certain conditions and requires critical analysis.
The prognostic value of fetal heart rate changes can be summarized as follows:
- In most cases, these changes precede the development of fetal acidosis, so they should be considered as early warning signs:
- Continuous CTG makes it easier to recognize typical deviations;
- Continuous recording is a basic requirement, since experience shows that even in severe acidosis, the fetal heart rate remains normal for a long time;
- Even with continuous recording of heart contractions and recognition of characteristic changes, it is impossible to quantitatively express the degree of fetal hypoxia.
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