Does a three-hour delayed pushing benefit the mode of delivery?

Abstract

The objective of this study was to compare two strategies for passive second stage management: three-hour vs two-hour delayed pushing after the diagnosis of full cervical dilation on mode of delivery and perinatal outcomes. This retrospective observational study included low-risk nulliparous women who reatched full cervical dilation under epidural analgesia with a single term fetus in cephalic presentation and normal fetal heart rate, between September and December 2016. Mode of delivery (spontaneous vaginal delivery versus operative delivery including cesarean section and instrumental vaginal delivery) and perinatal outcomes (post-partum hemorrhage, perineal lacerations, 5-min Apgar score, umbilical cord pH and transfer to neonatal intensive care unit) were compared between two maternity units: maternity unit A, where women could have up to a three-hour delayed pushing period after full cervical dilation diagnosis, and maternity unit B, where the delayed pushing period was a maximum of 2h. Outcomes were compared using univariate and multivariable analyses. Adjusted odds ratios (aOR) were estimated using a logistic regression multivariable model that included potential cofounders. During the study period, 614 women were included, 305 in maternity unit A and 309 in maternity unit B. Women's pre-existing characteristics were comparable between the two maternity units. Women delivering in the maternity unit A had significantly lower risks of having an operative delivery compared to women delivering in the maternity unit B (respectively 18.4vs 26.9%; aOR=0.64; 95%CI [0.43 - 0.96]). Perinatal outcomes were comparable in the two maternity units, particularly in terms of post-partum hemorrhage rates (7.4vs 7.8%; aOR=1,19 [0.65 - 2.19]). Increasing the possible length of the delayed pushing period from 2 to 3h after the diagnosis of full cervical dilation in low-risk nulliparous women appears to reduce operative deliveries without adverse effects on maternal or neonatal morbidity.