Impact of epidural analgesia on outcomes of vaginal birth after cesarean delivery.

Primary objective: To assess the association between Epidural Analgesia (EA) during Vaginal Birth After Cesarean (VBAC) and delivery mode (spontaneous or instrumental vaginal delivery). Secondary objectives include maternal and neonatal outcomes.

Methods: In this retrospective population-based cohort study, all women who underwent a VBAC with and without EA, between the years 1996-2016 at the Soroka University Medical Center (SUMC) were included. Women who delivered by cesarean section (elective and non-elective) and those who gave birth to a newborn with chromosomal abnormalities or major malformations, and multifetal gestations were excluded. Demographical, clinical, and obstetrical characteristics were recorded, and pregnancy complications and adverse perinatal outcomes were compared between the groups. The primary outcome was the type of delivery. Univariate analysis was followed by a multivariate analysis to control for confounders. A p value of < 0.05 was considered statistically significant.

Results: During the study period, 17,516 women who have had a previous CS met the inclusion criteria, of which 15% (n = 2652) used EA during labor, while the rest of the cohort 85% (n = 14,864) were non-EA users. Women in the EA group had higher rates of instrumental delivery and postpartum hemorrhage (PPH) as well as higher rates of oxytocin augmentation and a longer second stage of labor. The use of EA was found to be an independent risk factor for instrumental delivery after controlling for maternal age, ethnicity, parity, DM (diabetes mellitus), hypertensive disorders of pregnancy, oxytocin augmentation, prolonged second stage of labor, induction of labor, fertility treatments and oligohydramnios. However, no significant differences were observed regarding neonatal outcomes including perinatal mortality, birth weight, Apgar scores and shoulder dystocia rates.

Conclusion: EA for women undergoing a VBAC was associated with higher rates of instrumental delivery and PPH, oxytocin augmentation and a longer second stage of labor compared with women without EA. However, neonatal outcomes did not differ between the groups.