Isonicotinic acid hydrazide (INH): A new agent for cervical ripening at term

The aim of this study was to assess the efficacy and safety of intravaginal isonicotinic acid hydrazide (INH) compared with misoprostol for cervical ripening at term. In this randomised controlled trial, 150 pregnant women, scheduled for labour induction, with Bishop's score (BS) ˂5, were recruited. They were assigned randomly to vaginal administration of isonicotinic acid hydrazide (INH) (900 mg) or misoprostol (25 μg), which were repeated every 4 h up to 3 times as needed. The efficacy of medications were evaluated by predetermined primary and secondary outcome variables for cervical ripening and induction of labour and delivery. Within the first 12 h of study, there was a significant increase in BS in each group. However, in the INH group changes in of BS were greater 12 h after starting the medication (p = 0.04). In the INH group, labour induction was needed more frequently, and the time from start of medication to the beginning of the active phase of labour and to the time of delivery were significantly longer (p˂0.001). Vaginal INH is an effective agent for cervical ripening at term.