A prospective study for the effect of vaginal ph on dinoprostone gel for cervical ripening / labor induction

Abstract

Induction of labor is the artificial initiation of labor before its spontaneous onset by means of various interventions. Now a days, about 10-30% obstetric cases required induction due to various indications. There are many surgical and medical methods available for induction of labor/cervical ripening. Of these cervical ripening using Prostaglandin Gel intracervically is most common practice in modern times. Prostaglandin gel is not only effective in cervical ripening, but also effective in activating myometrial contractility. There are many formulations available for Prostaglandin E2 for local administration, including vaginal tablets, endocervical gels, and vaginal gels and also in the form of slow release dinoprostone vaginal insert forms. Prostaglandin E2 gel is an organic acid which has low solubility in aqueous solution with low pH. The aim of this study is to evaluate whether vaginal PH has any effect on Dinoprostone gel used for cervical ripening in labor induction. Aim 1. The influence of vaginal PH on the efficacy of PGE2 gel which we commonly use for cervical ripening in labor induction. So it might improve patient selection and we can predict those cases which might go into failed induction with PGE2. 2. I will also try to study the changes in vaginal pH because of various factors e.g. age of the patient, gestational age, parity, draining per vagina etc. Materials and Methods: This study was conducted on patients who were undergoing induction of labor with Dinoprostone (PGE2) gel at The Institute of social obstetrics, Government Kasturba Gandhi Hospital, Madras Medical College, Triplicane, Chennai, and Tamil Nadu during the academic year 2016-17. The study was done in 100 patients for duration of 1 year. Study Designs: Prospective observational study. Sample size: 100 Results: 60% of the study populations are in the age group of 21 to 28 year. 33% pregnant women had vaginal pH >4.5. 66% women were primigravidae, while the remaining 34% are multigravidas. Among 32 cases of draining P.V. vaginal pH >4.5 is seen in 20 cases, i.e. 62.5%.Among 100 cases of PGE2 gel induction, 83.7% cases show positive Bishops score changes after 6 hour of induction in pregnant women with higher vaginal pH of >4.5.If vaginal pH is >4.5, it was found that the time interval between gel to delivery is reduced to <12 hours in 77% of cases. Conclusion: we can see that assessing vaginal pH before induction can be an useful parameter in predicting the outcome of labour in pregnant women who are undergoing labour induction with PGE2 gel. However further research with a well designed pharmacological study with bigger study population is necessary to study the role of vaginal pH in absorption and overall efficacy of Dinoprostone gel which in future could increase the efficacy and reduce unwanted outcomes.