Effect of oxytocin and oral prostaglandin E2 on uterine contractility and fetal heart rate patterns.

The incidnce of uterine contractility and of abnormalities of fetal heart rate (FHR) pattern was determined in a series of 2,834 monitored gravid women with singleton pregnancies producing mature infants in vertex presentation. Those subjected to uterotonic agents for induction or augmentation of lbaor had significantly more tetanic contractions, baseline hypertonus, and coupling of contractions. Similarly, significantly more variable and late FHR decelerations occurred in stimulated labors, and these were concentrated primarily in those receiving oxytocin. The overall incidence of FHR decelerations associated with the use of prostaglandin E2 (PGE2) was comparable to that encountered in unstimulated labor. The similarity between the contractions of spontaineous labor and those labors produced by PGE2 is noted.