Labor induction with the prostaglandin E1 methyl analogue misoprostol versus oxytocin: a randomized trial

Abstract

Objective: To compare the safety and efficacy of intravaginal misoprostol versus intravenous (IV) oxytocin infusion for labor induction.

Methods: One hundred thirty patients were randomly assigned to one of two induction groups: 1) intravaginal misoprostol or 2) IV oxytocin by continuous infusion, with prior cervical ripening using prostaglandin (PG) E2 gel if necessary.

Results: Among 129 patients evaluated, 64 were allocated to the misoprostol group and 65 to the oxytocin group. Prostaglandin E2 gel was administered to 29 patients (45%) in the oxytocin group with unripe cervices. Uterine tachysystole occurred more frequently in patients in the misoprostol group (34.4%) than in the oxytocin group (13.8%) (P < .05). Nevertheless, no statistically significant differences were noted between the groups in intrapartum complications including uterine hyperstimulation syndrome, mode of delivery, and neonatal or maternal adverse outcomes. The interval from induction to vaginal delivery was significantly shorter in the misoprostol group (11 versus 18 hours; P = .004). In 74% of patients in the misoprostol group, only one intravaginal dose was required for successful labor induction.

Conclusions: Intravaginal administration of misoprostol safely and effectively induces labor while minimizing the expense associated with IV oxytocin infusion. The higher frequency of uterine tachysystole associated with the use of misoprostol did not increase the risk of adverse intrapartum or perinatal outcomes. The use of PGE2 gel for cervical ripening contributed to the longer induction-to-vaginal delivery interval noted in the oxytocin group. Clinical trials appear warranted to detail misoprostol's optimal route, dose, and schedule for labor induction and its safety.