Oral and vaginal misoprostol compared with dinoprostone for induction of labor: a randomized controlled trial

To evaluate the efficacy of oral and vaginal misoprostol compared with the standard regimen using dinoprostone for induction of labor.

We conducted a multicenter, randomized controlled trial in Cape Town, South Africa. A total of 573 women admitted for induction of labor were randomized to receive oral misoprostol, vaginal misoprostol, or the control, dinoprostone. Misoprostol was given orally or vaginally as a 50-microg dose at 6-hour intervals to a maximum of four doses. The dinoprostone gel was given as a 1-mg dose in the posterior fornix every 6 hours (maximum two doses).

There was no significant difference in vaginal delivery rate in 24 hours between the vaginal misoprostol and dinoprostone groups. However, significantly fewer women delivered vaginally in the oral misoprostol group compared with those in the dinoprostone group (relative risk 0.71, 99% confidence interval 0.51, 0.99). The median induction to vaginal delivery time in the vaginal misoprostol, oral misoprostol, and dinoprostone groups was 12 hours, 23 hours, and 14 hours, respectively. The cesarean rate was approximately 33% in all the groups. There were more cesareans performed for fetal distress in the vaginal misoprostol group compared with the dinoprostone group (relative risk 2.86, 99% confidence interval 1.49, 5.46). There was a higher incidence of tachysystole in the vaginal misoprostol group (5.8%) compared with the other two groups: oral misoprostol (0.8%) and dinoprostone (0.8%), but this difference was not statistically significant. There were no differences in maternal or fetal complications.

Vaginal misoprostol is as effective as dinoprostone in induction of labor, but it is associated with more tachysystole and cesarean sections for fetal distress compared with dinoprostone. Oral misoprostol results in fewer vaginal deliveries in 24 hours, but it is not associated with increased tachysystole or fetal distress.