Oral or vaginal misoprostol administration for induction of labor: A randomized, double-blind trial

Objective: To compare the efficacy and vaginal birth intervals after intravaginal or oral misoprostol for labor induction. Methods: One hundred seventy-eight women were randomized to one of two double-blind groups: 1) oral misoprostol 200 mu g and one-half tablet placebo intravaginal or 2) oral placebo tablet and one-half tablet of a 100-mu g misoprostol intravaginal (dose 50 mu g). Doses were repeated every 6 hours until labor was established (maximum of three doses). Results: Ninety-three subjects were assigned to oral misoprostol and 85 to intravaginal administration, Oral administration was accompanied by significantly shorter intervals to the onset of uterine contractility (133 +/- 78 minutes versus 168 +/- 93, P < .01) but a higher incidence of abnormal uterine contractile activity (tachysystole 38.7% versus 20.0%, P < .01; hyperstimulation syndrome 44.1% versus 21.2%, P < .01). No adverse maternal or neonatal outcomes were noted, nor were there differences in cesarean delivery rates or total lengths of labor. Conclusion: Oral administration of 200 mu g misoprostol has similar efficacy to intravaginal administration of 50 mu g but is associated with more frequent abnormal uterine contractility. (Obstet Gynecol 1998;92:810-3. (C) 1998 by The American College of Obstetricians and Gynecologists.)