The impact of vaginal pH on induction of labour outcomes: a meta-analysis of observational studies

The present meta-analysis evaluates the impact of an acidic vaginal pH on the progress of labour induction with dinoprostone and misoprostol. We searched Medline, Scopus, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL, Clinicaltrials.gov and Google Scholar databases for relevant studies. Meta-analysis was performed with Rstudio using the meta function and trial sequential analysis was used to evaluate the adequacy of sample size. Nine studies were retrieved that involved 809 patients. An acidic vaginal pH did not influence the efficacy of misoprostol or dinoprostone in terms of accomplishing a successful vaginal delivery (OR 0.62, 95% CI 0.29, 1.30). The interval to delivery was unaffected by the acidity of vaginal pH (Mean Difference 4.18 h, 95% CI −2.09, 10.45). In conclusion, vaginal pH does not seem to affect the potency of vaginally administered prostaglandins; therefore, moistening of vaginal tables with acetic acid does not seem reasonable until further evidence becomes available.