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

Abstract

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 microg and one-half tablet placebo intravaginal or 2) oral placebo tablet and one-half tablet of a 100-microg misoprostol intravaginal (dose 50 microg). 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 microg misoprostol has similar efficacy to intravaginal administration of 50 microg but is associated with more frequent abnormal uterine contractility.