Randomized double blind placebo controlled trial of outpatient cervical ripening with isosorbide mononitrate prior to induction of labor

ABSTRACT

Our aim was to examine the efficacy and safety of isosorbide mononitrate [IMN] for cervical ripening and labor induction. Two hundred and forty pregnant women of at least 41 week gestation with a bishop score <5 were selected for a double blind trial, to randomly receive either 60 mg of vaginal IMN or a vaginal placebo. Fifty-four percent treated with IMN went to active phase of labor compared to thirty-one percent in the placebo group [p<0.01]. Ninty-eight women in the study group had vaginal delivery compared to eighty-two women in the placebo group. Mean interval to active phase of labor had statistical differences between the two groups. Headache was the common side effect with moderate intensity in IMN group. Outpatient cervical ripening and labor induction with isosorbide mononitrate seems to be an effective, safe and well tolerated procedure. Although some of women experienced side effects, no serious clinical maternal or fetal adverse effects were diagnosed. The definitive clinical efficacy and safety need to be evaluated in larger series of patients