The impact of extending the second stage of labor on repeat cesarean section and maternal and neonatal outcome

Abstract

Objective: To evaluate the effects of extending the second stage of labor in women attempting a trial of labor after a cesarean section (TOLAC).

Method: A retrospective cohort study comparing maternal and neonatal outcomes following TOLAC over two periods: period I whose prolonged second stage was considered 2 h, and period II whose prolonged second stage was considered 3 h. The primary outcome was repeat cesarean delivery (CD) rate.

Results: Incidence of repeat CD was significantly lower in period II (18.1% vs 29.7%, P < 0.001). Incidence of uterine rupture was significantly higher in period II (P < 0.001). Instrumental delivery rates were significantly higher in period II (26.2% vs 15.6%, odds ratio [OR] 1.67, 95% CI 1.21-3.56, P < 0.001). Rates of third- and fourth-degree perineal lacerations, chorioamnionitis, and length of hospital stay were similar between groups. Incidence of fetal acidemia was significantly higher in period II (1.5% vs 0.7%, OR 2.14, 95% CI 1.32-5.63, P < 0.001), and incidence of neonatal intensive care unit (NICU) admission was significantly higher (2.5% vs 1.6%, P = 0.004).

Conclusion: Extension of the second stage of labor is associated with a decrease in repeat CD rate with a concomitant increase in instrumental delivery rates, uterine rupture, fetal acidemia, and NICU admissions. These findings may warrant further consideration of allowing a prolonged second stage in patients attempting TOLAC.

Keywords: cesarean delivery; instrumental delivery; neonatal outcomes; postpartum hemorrhage; second stage of labor; trial of labor after cesarean; vaginal birth after cesarean; vaginal delivery.