A double-blind comparison of the safety and efficacy of intravaginal misoprostol and prostaglandin E2 to induce labor

Abstract

Objective: Our purpose was to compare the safety and efficacy of intravaginally administered misoprostol versus prostaglandin E2 for labor induction in a double-blind, randomized trial.

Study design: One hundred three patients with indications for labor induction (including prelabor rupture of membranes) were randomized and received either misoprostol 50 micrograms or prostaglandin E2 (dinoprostone) 3 mg intravaginally. The dose was repeated 6, 24, and 30 hours after the first dose until active labor was achieved. For proper blinding, the drugs were prepared as identical-looking vaginal tablets.

Results: With use of a random number-generated table 52 patients were allocated to the misoprostol group and 51 to the prostaglandin E2 group. After exclusion of 3 patients, 50 in each group were evaluated. Delivery within 24 hours after administration occurred more often in the misoprostol group (70% vs 46% in the prostaglandin E2 group, p = 0.009), and fewer patients in this group needed more than two doses (12% vs 30%, p = 0.027). No difference in cesarean section rate (12% vs 14%, p = 0.67), fetal heart rate anomalies (33% vs 34%, p = 0.89), tachysystole (8% vs 14%, p = 0.37), hyperstimulation syndrome (0% vs 2%, not significant), meconium passage (28% vs 18%, p = 0.22), and fetal outcome (Apgar score at 1 and 5 minutes, arterial and venous umbilical cord blood pH, transfer to neonatal intensive care unit) was noted between the two groups.

Conclusion: Intravaginal misoprostol is a safe drug for labor induction with superior effectiveness compared with intravaginal prostaglandin E2.