Effect of vaginal pH on the efficacy of the dinoprostone vaginal insert for cervical ripening in patients with an unfavorable bishop score

Abstract Objective: The aim of this study was to evaluate the effect of vaginal pH on the efficacy of the dinoprostone vaginal insert for cervical ripening in patients with unfavorable Bishop Score. Methods: Prospective observational cohort study, conducted at a Portuguese tertiary hospital. Term pregnant women with a singleton pregnancy and vertex presentation who had indication for labor induction with Bishop's Score ≤ 6 were included. Vaginal pH was measured with high accuracy strips before vaginal examination for Bishop Score was performed. The intravaginal dinoprostone insert (Propess®) was then applied into the posterior fornix. The primary outcome was the change of the Bishop's Score before placement and after removal of the dinoprostone insert. Spearman correlation was analyzed (SPSS 16.0). Results: A total of 75 women were included, with a gestational age of 39 ± 1,2 weeks. Mean initial vaginal pH was 4.67 ± 0.51. Mean variation of Bishop Score was 1.8 ± 2.3 points. There was a weak correlation between vaginal pH and changes on the Bishop Score with dinoprostone vaginal insert use (ρ = −0.123; p = 0.3). Conclusion: Vaginal pH does not appear to be a major influencer of the efficacy of dinoprostone vaginal insert for cervical ripening.