Department of Obstetrics and Gynecology, Sri Manakula Vinayagar Medical College and Hospital, Puducherry, India.
Fertility Consultant, Apollo Fertility, Chennai, India.
J Obstet Gynaecol. 2022 Feb;42(2):228-231. doi: 10.1080/01443615.2021.1904225. Epub 2021 May 21.
The purpose of this study was to assess the effect of vaginal pH on efficacy of intracervical dinoprostone gel (PGE2) for labour induction, progression and induction delivery interval. A cross-sectional study was done among 150 term pregnant women planned for induction with unfavourable Bishop's score ≤5. Women were categorised into two groups based on vaginal pH >4.5 and ≤4.5. Induction was done with maximum of three doses of PGE2 based on Bishop's score, followed by oxytocin administration. Failed induction rate was 14.5%. There was no significant association between vaginal pH and Bishop's score change after first gel application. There was no significant difference in failed induction rates, time from induction to active labour as well as induction delivery interval between two groups. Similarly, there was no significant association between oxytocin requirement and mode of delivery with vaginal pH. Intracervical PGE2 is an ideal route, unaffected by vaginal pH.Impact Statement Prostaglandins are organic acids that have diminished solubility in aqueous solution with a low pH. The release of the drug could be altered by the acidity of vagina and this could result in variable clinical response. Vaginal pH may alter the efficacy of intravaginally administered prostaglandins through several potential mechanisms. There was no significant effect of change in vaginal pH on effectiveness of intracervical administered PGE2. There was no significant association between vaginal pH and time from induction to time women is entering into active labour as well as time from induction to delivery. Similarly, there was no significant association between mode of delivery and oxytocin usage with vaginal pH in labour. Intracervical PGE2 is an ideal route, unaffected by vaginal pH. Further randomised studies are required comparing both vaginally administered PG inserts and intracervical PGE2 gels with vaginal and cervical pH, to directly compare their effectiveness in labour induction.
本研究旨在评估阴道 pH 值对经阴道应用地诺前列酮凝胶（PGE2）促宫颈成熟、进展及引产至分娩的影响。本研究为一项横断面研究，纳入 150 例拟行引产且 Bishop 评分≤5 的足月孕妇。根据阴道 pH 值＞4.5 和≤4.5 将孕妇分为两组。根据 Bishop 评分，给予最大剂量的 PGE2 凝胶诱导，继以催产素治疗。引产失败率为 14.5%。首次应用 PGE2 凝胶后，阴道 pH 值与 Bishop 评分变化之间无显著相关性。两组间引产失败率、引产至活跃期的时间及引产至分娩的时间均无显著差异。同样，催产素的需求和分娩方式与阴道 pH 值之间也无显著相关性。经阴道 PGE2 是一种理想的途径，不受阴道 pH 值的影响。
研究结论 前列腺素有降低水溶性的特点，低 pH 值时其溶解度降低。药物的释放可能会受到阴道酸度的影响，从而导致临床反应的变化。阴道 pH 值可能通过多种潜在机制改变经阴道给予的前列腺素的疗效。阴道 pH 值的变化对经宫颈给予 PGE2 的疗效无显著影响。阴道 pH 值与引产至进入活跃期的时间以及引产至分娩的时间之间无显著相关性。同样，分娩方式和催产素的使用与阴道 pH 值之间也无显著相关性。经阴道 PGE2 是一种理想的途径，不受阴道 pH 值的影响。需要进一步进行随机研究，比较经阴道给予 PG 栓剂和经宫颈给予 PGE2 凝胶与阴道和宫颈 pH 值的相关性，以直接比较它们在引产中的有效性。
