Evaluation of isosorbide mononitrate for cervical ripening prior to induction of labor for postdated pregnancy in an outpatient setting

Objective: To determine the safety and effectiveness of self-administered treatment with isosorbide mononitrate (IMN) for cervical ripening in Indian women with postdated pregnancies. Methods: A randomized, placebo-controlled study was conducted with 200 women with postdated pregnancies and unfavorable cervices who self-administered vaginally either 2 40-mg tablets of IMN or 2 40-mg tablets of pyridoxine as placebo prior to admission for induction of labor. The main outcome variables were change in Bishop score, time from admission to delivery, and presence or absence of fetal and maternal morbidity. Results: The Bishop score was significantly improved 24 hours after initiation of the outpatient IMN treatment (P<0.001) and the needs for further cervical ripening and oxytocin infusion were less in the study than in the control group (P<0.001 and P=0.008). The time from admission to delivery was also less (P<0.001). Moreover, the IMN treatment had no major adverse maternal or fetal effects. The vast majority of women in both groups were either satisfied or very satisfied with the outpatient treatment. Conclusion: The self-administration, at home, of isosorbide mononitrate leads to a safe and effective cervical ripening prior to labor induction in women with postdated pregnancies. CTRI Registration No.: CTRI/2011/091/000121 (C) 2012 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.