Use of Papaverine to Shorten the Second Stage/Duration of Labor in Pregnant Women After Cervical Ripening by Double-balloon Catheter

This prospective, randomized, double-blind controlled trial aims to evaluate whether intravenous papaverine, administered immediately after the removal of a double-balloon catheter used for cervical ripening, can shorten the duration of labor in term pregnant women undergoing induction of labor. Papaverine is an antispasmodic medication that relaxes smooth muscle and is commonly used in obstetrics, although its effect on labor progression following mechanical cervical ripening has not been fully studied. Eligible participants include nulliparous and multiparous women with a singleton pregnancy at 37-42 weeks, admitted for induction of labor with a double-balloon catheter. After catheter removal, participants will be randomized in a 1:1 ratio to receive either 80 mg intravenous papaverine or placebo (normal saline), administered by the midwife who is not involved in clinical decision-making. Clinical staff and participants will remain blinded to group allocation. The primary outcomes are the time from drug administration to complete cervical dilation and the duration of the second stage of labor. Secondary outcomes include mode of delivery, maternal complications (such as perineal tears and postpartum hemorrhage), oxytocin augmentation duration and maximum dose, and neonatal outcomes. This study seeks to determine whether papaverine can safely and effectively reduce labor duration following mechanical cervical ripening.