The effect of tablet moistening on labor induction with intravaginal misoprostol: a randomized trial

Abstract

Objective: To estimate whether a dosage of 50 microg of misoprostol tablets moistened with 3% acetic acid and administered intravaginally is more efficacious for labor induction than a similar dosage regimen using dry tablets.

Methods: A total of 177 women who presented with an indication for cervical ripening and labor induction were randomly assigned to one of two treatment groups: 1) intravaginal misoprostol in dry tablet form, or 2) intravaginal misoprostol moistened with 1 mL of 3% acetic acid solution. The primary outcome assessed was the interval from start of induction to vaginal delivery. To detect at least a 3.5-hour difference in the primary outcome with 80% power, 87 subjects were required in each group.

Results: Among 162 patients evaluated, 80 were allocated to the misoprostol dry group and 82 to the misoprostol moistened group. No significant difference was noted for the mean +/- standard deviation interval to vaginal delivery: 1130 +/- 636 minutes for the group who received dry tablets and 1004 +/- 636 minutes for those who received moistened misoprostol tablets (P =.25). Additionally, no statistically significant differences were noted between the groups with respect to need for oxytocin, proportion of patients delivered after a single dose, intrapartum complications (including tachysystole and uterine hyperstimulation), mode of delivery, or perinatal outcomes.

Conclusion: Tablet moistening with 3% acetic acid solution does not seem to improve the efficacy of intravaginally administered misoprostol for labor induction.