Effect of Vaginal PH on Efficacy of Dinoprostone Gel for Labour Induction: A Cross-Sectional Study in Eastern India

Objectives: To evaluate whether vaginal pH alters the efficacy of dinoprostone gel for induction of labor, to find out whether vaginal pH affects cervical ripening and Bishop’s score prior to induction, and to evaluate whether parity or age affects vaginal pH. Materials and Methods: This prospective study was conducted at a tertiary care center in Kolkata for a period of 18 months, and included 200 women undergoing induction with dinoprostone gel. Participants were categorized based on vaginal pH: Group A (pH ≤4.5) and Group B (pH >4.5). The primary outcomes that were assessed included changes in Bishop’s score, time to active labour, and mode of delivery. Results: The majority of participants were aged 21-25 years, with a significant association found between higher vaginal pH and gravidity (P=0.002). Group B demonstrated greater mean changes in Bishop’s score after 12 hours (5.70 vs. 4.19), a lower need for repeat gel (57.34% vs. 78%), and a shorter induction-to-active labour duration (13.97 vs. 17.98 hours) compared to Group A. Furthermore, caesarean section rates were notably lower in Group B (24.26% vs. 51.5%). Conclusion: The study concludes that parity affects vaginal pH, which in turn significantly impacts labour induction outcomes with dinoprostone gel. Higher vaginal pH correlates with improved induction success, prompting further research to explore this relationship in a larger, randomized context. These findings indicate that higher vaginal pH positively influences the efficacy of dinoprostone gel in labour induction. The results align with some of the previous studies highlighting the role of vaginal pH in drug release and absorption, suggesting that measuring vaginal pH could enhance patient selection and improve induction outcomes.