Objective: To compare the efficacy and safety of a single dose of 50 μg oral misoprostol with 25 μg vaginal misoprostol for labor induction.
Material and Method: This study was a randomized, double-blind controlled trial conducting in pregnant women admitted at delivery room, Department of Obstetrics and Gynecology, Bangkok Metropolitan Administration
Medical College and Vajira Hospital between March 2002 and January 2005. All 146 pregnancies at > 37 weeks’ gestation who had indication for labor induction with unfavorable cervix were randomly divided into a group of single dose of 50 μg misoprostol orally or 25 μg misoprostol vaginally. Initial and six hours after misoprostol administration, Bishop scores were evaluated. Requirement of oxytocin augmentation, complication due to uterine hypertonus, incidence of vaginal delivery, Apgar score at 1 and 5 minutes, and number of neonate admitted at neonatal intensive care unit (NICU) were recorded.
Results: The baseline characteristics and median initial Bishop scores were comparable in both groups. At 6 hours after misoprostol administration the median cervical changes of women who received oral or vaginal misoprostol were statistically significant different, 3 and 4, respectively. The median time interval to vaginal delivery of women who received oral misoprostol was significantly longer than of those who had vaginal drug, 16.9 and 11.8 hours respectively. Comparable neonatal outcomes were found in both groups in terms of assigned Apgar score at 1 and 5 minutes.
Conclusion: A single dose of 25 μg vaginal misoprostol appears to be more effective than 50 μg oral dose in improving Bishop scores and decreasing the time to vaginal delivery in women with unfavorable cervix without severe adverse effects.

Keywords: Labor induction, Cervical ripening, Single dose misoprostol, Oral, Vaginal