Epidural analgesia during labour: a retrospective cohort study on its effects on labour, delivery and neonatal outcome

Objectives: to evaluate the impact of epidural analgesia (EA) on labor, delivery and neonatal status. Material and methods: retrospective, observational, cohort study comprising 5593 pregnant women who met the inclusion criteria (singleton pregnancy, cephalic presentation, 37-42 weeks of gestation). Out of them, 2496 had EA and 3097 constituted the control group. Main outcome measures: incidence of labor complications and operative deliveries in women who received EA, neonatal status assessed by Apgar score in 1- and 5-minute, and cord pH values. Results: Labor complications were more frequently observed in the epidural group, with an almost 1.5-fold higher incidence in nulliparous (16.32% vs. 11.29%) and 1.4-fold in multiparous women (9.86% vs. 7.08%). Stepwise logistic regression confirmed that EA is a significant risk factor for labor complications in nulliparous women (OR 1.27, 95% CI 1.03-1.58) and for forceps delivery in multiparous women (5.20, 95% CI 3.31-8.17). Also, EA is an important risk factor for both, low cord arterial pH <7.10 (OR 1.98, 95% CI 1.28-3.09, p=0.0023) and low Apgar score at 1 minute (OR=4.55, 95% CI 2.35-8.80, p<0.0001). Crucially, there was no difference in the incidence of a low Apgar score at 5 minutes. Conclusions: EA constitutes an independent risk factor for operative vaginal delivery in multiparous women, but has no effect on the incidence of cesarean sections, either in nulliparous or multiparous women. EA also increases the risk of labor complications, low 1-minute Apgar score and low umbilical cord pH, but is not associated with low 5-minute Apgar score.