Perinatal heart rate variability and circulatory adaptation in association with normal labor and after elective cesarean section.
Heart rate variability and basal hemodynamic parameters were studied in connection with 20 normal deliveries and after 16 elective cesarean sections. Eight of the cesarean sections were performed with the use of maternal barbiturate anesthesia and eight with the use of epidural blockade. The interval index describing the long-term variability and the differential index describing the short-term variability of the heart rate were measured continuously from 10-minute samples of a direct fetal electrocardiogram and a neonatal electrocardiogram of the infants by a microprocessor-based system. In association with normal labor, significant increases in both indices of variability were observed during the second stage of labor and during the first 2 hours of extrauterine life. After elective cesarean section both indices of neonatal heart rate variability remained significantly lower than those after normal labor. However, a significant increase was observed in the differential index of the infants delivered with the use of epidural blockade. During the neonatal period, simultaneous recordings of basal heart rate, systolic and diastolic blood pressures, and rectal and heel temperatures were made at 10-minute intervals. The basal neonatal heart rate was significantly higher in both cesarean section subgroups compared with that after normal labor. A significant decrease in basal neonatal heart rate during the second hour of life was observed after normal labor and after cesarean section with the use of epidural blockade. Systolic blood pressures in newborn infants delivered with the use of maternal epidural blockade were equal to those after normal labor, but higher than those after cesarean section with barbiturate anesthesia. Newborn infants after elective cesarean section had significantly lower diastolic blood pressures than infants delivered normally, but there was no difference in the diastolic blood pressures between the two cesarean section subgroups. The infants delivered vaginally had lower heel temperatures than those delivered abdominally. According to the present study, the neonatal circulatory adaptation after elective cesarean section is different from that after normal delivery; however, the neonatal hemodynamics after cesarean section with epidural blockade more closely resemble the situation after normal labor.
D000773:Anesthesia, Obstetrical; D001463:Barbiturates / Q000008:administration & dosage; D001794:Blood Pressure; D002585:Cesarean Section / Q000379:methods; D004562:Electrocardiography; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D005323:Fetal Monitoring; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D007743:Labor, Obstetric; D011247:Pregnancy
D001463:Barbiturates