TO DETERMINE THE EFFECT OF VAGINAL PH ON EFFICACY OF DINOPROSTONE GEL FOR LABOUR INDUCTION-PROSPECTIVE OBSERVATIONAL STUDY

Abstract

Introduction: Induction of labour (IOL) has been increased significantly in the recent days. It is widely acknowledged that IOL is appropriate when the potential benefits for the fetus, mother, or both outweigh those of expectant management, which involves waiting for spontaneous labour to begin. Among the many pharmacological methods of labour induction, prostaglandins like dinoprostone gel are a widely used method. The success of IOL depends on several factors including the clinical condition of the patient at the time of induction, induction methods, pH of the vagina and other predictive factors. Given the complexity of factors influencing the success of labour induction, including biochemical, physiological, and clinical parameters, this study explores the specific role of vaginal pH in modifying the efficacy of PGE2 gel-based labour induction methods. Understanding these interactions will provide critical insights into optimizing induction protocols, potentially improving maternal and fetal outcomes. Objectives: To determine the vaginal pH and classify as high (pH >4.5) and low vaginal pH (pH ≤4.5); and to determine if the vaginal pH has any effect on the action of PGE2 gel for cervical ripening and labour induction. Methods: A prospective observational study was conducted in the department Obstetrics and Gynaecology of RL Jalappa Hospital, Kolar. All pregnant women underwent IOL during the study period were eligible for the study. Ninety participants with singleton pregnancy with cephalic presentation, having unfavourable modified Bishop score (≤ 5) and reactive NST were included in the study after obtaining informed consent. However, patients with known conditions including hypersensitivity to prostaglandins, placenta previa, suspected chorioamnionitis, malpresentation, cephalopelvic disproportion, previous caesarean delivery, and premature rupture of membranes were excluded from the study. xxii | P a g e The participating patients were clinically evaluated after taking a detailed obstetric, menstrual and medical history, supported by relevant investigations. Each participant underwent speculum examination and vaginal pH was assessed by using pH indicator paper. Based on the pH, patients were divided into two groups- Group A (pH ≤4.5) and Group B (pH >4.5). Following this, Modified Bishop score is assessed at the baseline and during subsequent follow-up vaginal examinations. All clinical assessments were done by the investigators according to the standard protocol of the hospital. Standard ethical practices were followed during the study. Results: The study included 90 term pregnant participants with equal distribution of low and high vaginal pH. The baseline characteristics of both groups like mean age, gestational age, parity, comorbidities, and pre-induction modified Bishop score was similar. Significant differences were noted between the two groups in favour of group B. Mean Bishop score improvement in group B (4.78 ±1.72) was high compared to group A (2.5 ±1.1). The dose repetitions were less among patients having a high vaginal pH. The mean time taken enter active phase of labour was substantially higher in group A (16.2 hours) compared to the group B (9.2 hours) participants. The proportion of normal delivery was significantly higher in group B (64.5%) compared to group A (40.0%). Conversely, group A had a high rate of LSCS (60.0%) compared to group B (35.5%). Conclusion: This study reveals that patients with higher vaginal pH (>4.5) experience better outcomes with dinoprostone-induced labour. Appreciable favourable outcomes were noted in cervical ripening, reduced induction requirements, and higher rates of normal delivery. These findings highlight the importance of examining the vaginal pH in predicting successful labour induction.