Effects of intracervical prostaglandin E2 on fetal heart rate and uterine activity patterns in the presence of oligohydramnios

OBJECTIVE: Our purpose was to compare fetal heart rate patterns and uterine activity before and after preincubation prostaglandin E2 administration in the presence or absence of oligohydramnios. STUDY DESIGN: In a retrospective case-controlled review we examined cases in which prostaglandin E2 (Prepidil) was inserted intracervically for gravid women requring an induction of labor in the presence of either oligohydramnios (amniotic fluid index ≤5.0) or adequate fluid (amniotic fluid index 5.1 to 23.9). Uterine activity and fetal heart rate tracings that were begun 1 hour before and continued for 6 hours after dosing were interpreted without knowledge of amniotic fluid volume. RESULTS: Cases in the olgiohydramnios (n = 51) and adequate fluid (n = 49) groups were the same for maternal age, race, parity, gestational age, and predose Bishop score. Patients with oligohydramnios had more high-amplitude contractions in the first hour after dosing (9.0 ± 1.2 vs 6.1 ± 0.9, p< 0.05), but there were no significant differences in the frequency or duration of contractions during the subsequent 5 hours. Uterine hyperstimulation was not seen, and there were no differences in the frequency of variable or late fetal heart rate decelerations. CONCLUSION: For pregnancies undergoing preinduction cervical ripening with intracervical prostaglandin E2, the presence of oligohydramnios was not associated with a greater risk of fetal heart rate decelerations, although contractions were more common during the first hour after dosing.