BackgroundIntravenous calcium administration has shown promise in enhancing uterine contractions and reducing blood loss during cesarean section, but this regimen has not been compared in vaginal labor induction. ObjectiveTo determine the efficacy of oxytocin combined with calcium versus oxytocin alone for inducing labor among women with term premature rupture of membranes (PROM). Study designThis single-blind, randomized control trial was conducted between October 2022 and May 2023 in a tertiary university hospital. Patients diagnosed with PROM were randomly allocated into two groups. The intervention group received a bolus of 10 mL of calcium gluconate followed by a continuous infusion of oxytocin via a pump (n = 210), whereas the control group received only oxytocin infusion (n = 218). The primary outcome was successful vaginal deliveries within 24 hours of labor induction. Secondary outcomes included the interval from labor induction to delivery, vaginal delivery blood loss, and maternal and neonatal complications. ResultsBaseline characteristics, including maternal age, BMI, Bishop score before labor induction, were comparable between groups. The rate of vaginal delivery within 24 hours of labor induction was statistically higher in the intervention group (79.52% vs. 70.64%; P = 0.04). Participants in intervention group experienced a shortened interval between induction and delivery (10.48 h vs. 11.25h; P = 0.037), and demonstrated a higher success rate in induction of labor assessed by the onset of active phase (93.80% vs. 87.61%; P = 0.04) without increasing the cesarean rate. Reduced hemorrhage was presented in the intervention group (242.5ml vs. 255.0ml; P = 0.0015) while the maternal and neonatal outcomes were comparable between groups. ConclusionThe co-administration of calcium and oxytocin in labor induction among pregnancies with PROM was more efficient and safer than oxytocin alone. Our research suggests that the combination therapy of calcium and oxytocin may offer significant advantages during the process of labor induction and result in better outcomes.