Intrapartum fetal heart rate monitoring. VII. The impact of mode of delivery on fetal outcome.

The condition of 1,991 fetuses just prior to delivery was assessed in a semiquantitative manner by means of a fetal heart rate (FHR) score. A comparison between types of delivery was made for groups with identical FHR scores to test the hypothesis that the differences in lower Apgar score rates were consequences of the type of delivery rather than differences in prenatal condition. For each of several FHR scoring categories, the differences in rates of low Apgar scores between spontaneous vaginal deliveries and cesarean sections were consistently different in favor of the vaginally delivered group. No such difference was observed when spontaneous vaginal deliveries were compared with low-forceps deliveries. Breech deliveries, when compared to spontaneous vaginal deliveries, resulted in a higher rate of low 1-minute Apgar scores. Five-minute Apgar scores were significantly different only if the breech delivery was preceded by abnormal FHR patterns.