Prospective randomized clinical trial of inpatient cervical ripening with stepwise oral misoprostol vs vaginal misoprostol.

OBJECTIVE: The purpose of this study was to compare the efficacy and safety of stepwise oral misoprostol vs vaginal misoprostol for cervical ripening before induction of labor.

STUDY DESIGN: Two hundred and four women between 32 to 42 weeks of gestation with an unfavorable cervix (Bishop score < or = 6) and an indication for labor induction were randomized to receive oral or vaginal misoprostol every 4 hours up to 4 doses. The oral misoprostol group received 50 microg initially followed by 100 microg in each subsequent dose. The vaginal group received 25 microg in each dose. The primary outcome was the interval from first misoprostol dose to delivery. Patient satisfaction and side effects were assessed by surveys completed after delivery.

RESULTS: Ninety-three (45.6%) women received oral misoprostol; 111 (54.4%) received vaginal misoprostol. There was no difference in the average interval from the first dose of misoprostol to delivery in the oral (21.1 + 7.9 hrs) and vaginal (21.5 + 11.0 hrs, P = NS) misoprostol groups. The incidence of hyperstimulation in the oral group was 2.2% vs 5.4% in the vaginal group, P = NS. Eighteen patients in the oral group (19.4%) and 36 (32.4%) in the vaginal group underwent cesarean section (P < .05). This difference was attributed to better tolerance of more doses of misoprostol by the women in the oral group. There was no difference in side effects (nausea, vomiting, diarrhea, shivering) between groups. Fourteen percent of women in the vaginal group versus 7.5% in the oral group were dissatisfied with the use of misoprostol (P = NS).

CONCLUSION: Stepwise oral misoprostol (50 microg followed by 100 microg) appears to be as effective as vaginal misoprostol (25 microg) for cervical ripening with a low incidence of hyperstimulation, no increase in side effects, a high rate of patient satisfaction, and is associated with a lower cesarean section rate.