The Effect of Vaginal Magnesium Sulfate on Cervical Ripening Prior to Labor Induction: A Randomized Clinical Trial

Background and Aim: Considering the effect of magnesium sulfate on the progression of effacement, dilation, and duration of labor, and given the undesirable consequences of prolonged labor and the necessity to prevent its occurrence, this study was conducted with aim to determine the effect of vaginal magnesium sulfate on cervical ripening prior to labor induction.Methods: This triple-blind randomized controlled clinical trial study was conducted on 104 pregnant women referred for vaginal delivery at Razi and Imam Khomeini hospitals, Ahvaz in 2023. The participants were randomly allocated to two groups (n=52 in each group) through balanced block randomization. After initial Bishop score assessment, participants received either placebo or magnesium sulfate. Secondary Bishop scores were assessed after 3 hours. Labor duration and active phase of labor were recorded using a partogram.Results: The two groups were homogenous in terms of age, BMI, and fetal weight (P > 0.05). The intervention group compared to the control group had a significantly higher gestational age at delivery (39.17±1.45 weeks vs. 38.48±1.58 weeks, P=0.022). The secondary Bishop score was significantly higher in the intervention group (6.06±1.48 vs. 5±1.43, P<0.001). Additionally, the total time of vaginal delivery in the intervention group was significantly lower than that in the control group (420.1±124.45 vs. 485.43±192.3, P=0.042). There was no significant difference between the two groups in terms of delivery method (P=0.604).Conclusion: The results showed that vaginal magnesium sulfate exhibited a significantly higher secondary Bishop score, indicating improved cervical ripening, and a shorter total time of vaginal delivery. Overall, vaginal magnesium sulfate may be a valuable adjunct in optimizing labor induction outcomes.