Cervical ripening before induction of labor: a randomized trial of prostaglandin E2 gel versus low-dose oxytocin

Abstract

Objective: The purpose of this study was to compare prostaglandin E2 gel and a low-dose infusion of oxytocin for cervical ripening before labor induction.

Study design: A total of 158 women were randomized to receive either two intracervical doses of 0.5 mg prostaglandin E2 gel 6 hours apart or 12 hours of intravenous oxytocin up to 4 mlU/min. After cervical ripening labor was induced with high-dose oxytocin infusion and amniotomy.

Results: There was no difference between the prostaglandin E2 and low-dose oxytocin groups in the likelihood of being in labor or having a Bishop score favorable for induction after ripening (64.2% vs 52.0%, p = 0.12) or in the incidence of vaginal delivery (75.9% vs 74.7%). Prostaglandin E2-treated patients were delivered sooner (20.2 +/- 8.1 hours vs 25.0 +/- 10.5 hours, p = 0.002). Among delivered patients the likelihood of vaginal delivery within 24 hours was greater with prostaglandin E2 ripening (63.7% vs 47.2%, p = 0.04), but there was no difference at 36 hours (76.2% vs 75.0%). Uterine hyperstimulation and fetal distress during ripening occurred only in the prostaglandin E2 group, at a rate of 4.8%.

Conclusions: After cervical ripening with prostaglandin E2 gel or low-dose oxytocin vaginal delivery can be expected in three fourths of patients within 24 to 36 hours. We recommend that patients with an unfavorable cervix who require delivery undergo cervical ripening and induction of labor rather than automatic delivery by cesarean section.