Cervical ripening with self administered iso sorbide mononitrate vaginally, in uncomplicated singleton pregnancies at 39 weeks gestation: a double blind randomised controlled trial

Abstract

Introduction Vaginal iso sorbide mononitrate (ISMN) is effective in pre induction cervical ripening in post dated pregnancies. Objectives To determine the effectiveness and acceptability of ISMN self-administered vaginally at home, in causing cervical ripening in uncomplicated singleton pregnancies at 39 weeks gestation. Methods Consecutive women with uncomplicated singleton pregnancies, presenting between 01 October 2013 and 31 March 2014, with a modified Bishop score (MBS) of < 5 at a gestational age (GA) of 273 days to the University Obstetric Unit of Teaching Hospital Mahamodera Galle, were allocated by stratified (primip/multip) block randomisation to self-administer vaginally at home every other day, five doses of 60 mg of sustained release form of ISMN (ISMN-SR); (n = 72, cases), or pyridoxine 10 mgs (n=72, controls), from GA 273 to 282 days. Results The mean MBS and the mean change of MBS at 282 days, and the proportions with spontaneous onset of labour (SOL) by GA 282 days, were not significantly different between the two groups. A vast majority were satisfied with outpatient therapy (80% cases vs.76% controls), were happy to use it in a subsequent preg-nancy (89% cases vs. 86% controls) and would recom-mend it to a friend (93% cases vs. 90% controls). Conclusions Home adminstrated vaginal ISMN therapy from GA 39 weeks was not effective in causing significant cervical ripening or promoting SOL, but it was acceptable to women.