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

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.

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.

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.

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