A comparison of various routes and dosages of misoprostol for cervical ripening and the induction of labor

OBJECTIVE: The purpose of this study was to compare the efficacy of differe nt routes of misoprostol administration for cervical ripening and the induc tion of labor. STUDY DESIGN: Three hundred thirty women at greater than or equal to 32 wee ks gestation with a Bishop score less than or equal to6 and an indication f or induction were randomized to 1 of 3 double-blinded groups: (1) 25 mug or ally administered misoprostol plus 25 tg vaginally administered misoprostol , (2) orally administered placebo plus 25 mug vaginally administered misopr ostol, or (3) 25 tg orally administered misoprostol plus vaginally administ ered placebo. Doses were repeated every 4 hours until onset of labor or a m aximum of 12 doses were given. The primary outcome of the trial was vaginal delivery within 24 hours of the initiation of induction. Secondary outcome s were the time from induction to delivery, need for oxytocin augmentation, mode of delivery, frequency of side effects, and neonatal and maternal out come. Analysis of variance, chi-square test, and logistic regression were u sed for analysis. RESULTS: There were no significant differences In maternal characteristics or Indications for induction. The percentage of women who achieved vaginal delivery within 24 hours was highest in the vaginally administered misopros tol group: 67% compared with 53% In the oral-plus-vaginal group (P < .05) a nd 36% in the oral group (P < .05). The median time to vaginal delivery was shorter in the vaginal and oral-plus-vaginal misoprostol groups, 13.5 hour s and 14.3 hours, respectively, when compared with 23.9 hours in the oral g roup (P < .05). The rate of cesarean delivery was lowest in the vaginal mis oprostol group (17% compared with 30% In the oral-plus-vaginal group and 32 % in the oral group; P < .05). Uterine tachysystole occurred least frequent ly in the oral misoprostol group (10% compared with 32% in the vaginal grou p and 34% in the oral-plus-vaginal group; P < .05). Uterine hyperstimulatio n also occurred least frequently in the oral misoprostol group (4% compared with 15% in the vaginal group and 22% in the oral-plus-vaginal group; P < .05). CONCLUSION: At the doses studied, induction of labor with vaginally adminis tered misoprostol is more efficacious than either oral-plus-vaginal or oral -only route of administration.