Oral versus vaginal misoprostol for induction of labor: a double-blind randomized controlled trial.

OBJECTIVE: To determine the efficacy of oral misoprostol (50 microg) administered every 3 hours compared to vaginal misoprostol (50 microg) administered every 6 hours for induction of labor.

STUDY DESIGN: In this double-blind randomized trial, 126 women received misoprostol (50 microg) either orally every 3 hours or vaginally every 6 hours for induction of labor. Outcomes included time from induction to delivery, oxytocin augmentation, incidence of hyperstimulation and tachysystole, mode of delivery, and neonatal outcomes.

RESULTS: Median time to delivery was shorter in those women who were receiving vaginal misoprostol (vaginal 14.3 hours vs oral 23.1 hours; P =.0004) and more women in the oral group required oxytocin augmentation of labor (73% vs 42%) (RR, 1.98; 95% CI, 1.29 to 3.06). The incidence of hyperstimulation was similar between the groups, but there was an increased incidence of tachysystole in the vaginal group (26.5% vs 9.7%)(RR, 2.74; 95% CI, 1.16 to 6.51). There was no difference between the groups with respect to mode of delivery or neonatal outcome.

CONCLUSION: Vaginal misoprostol administered every 6 hours is more effective for induction of labor than oral misoprostol administered every 3 hours. The higher rates of tachysystole with use of vaginal misoprostol in the current study warrant further investigation.