Safety and efficacy of misoprostol orally and vaginally: a randomized trial

To compare the safety and efficacy accompanying oral and vaginal misoprostol for cervical ripening.

One thousand four women with medical or obstetric indications for labor induction and unripe cervices were randomly assigned to receive oral or vaginal misoprostol. Initial doses of 200 microg oral and 50 microg vaginal misoprostol were increased to 300 microg oral and 100 microg vaginal after two doses, to a maximum of six doses. Misoprostol was given every 6 hours in both groups. We anticipated that 11% of women treated vaginally would require intervention during the ripening process. Intervention was defined as interruption of the ripening process before labor or Bishop score of 7 or a lack of response to six misoprostol doses.

Five hundred three subjects were assigned to oral and 501 to vaginal administration. Oral misoprostol was associated with significantly higher frequencies of intervention (67 [13.3%] versus 42 [8.4%], P =.01), tachysystole (114 [23.6%] versus 85 [17.6%], P =.02), and hyperstimulation (90 [18.6%] versus 66 [13.7%], P =.04). There were no significant differences in cesarean rates (147 [29.2%] versus 120 [24.0%], P =.06), mean number of misoprostol doses used (1.5 versus 1.6, P =.18), or hours from drug administration to delivery (24.5 versus 25.4, P =.77) between the oral and vaginal groups, respectively. The numbers of deliveries between the groups within 24 hours was different (271 [56%] versus 290 [60%], P =.02), oral and vaginal, respectively. No adverse neonatal outcomes were noted.

Oral misoprostol has similar efficacy as vaginal misoprostol but is associated with a higher frequency of excessive uterine contractility and intervention.