Epidural Analgesia and Fetal Head Malposition at Vaginal Delivery

Abstract

In Brief Objective To determine if nulliparas who delivered with on-demand epidural analgesia are more likely to have malpositioning of the fetal vertex at delivery than women delivered during a period of restricted epidural use. Methods A retrospective cohort of nulliparous women with spontaneous labor delivered during a 12-month period immediately before the availability of on-demand labor epidural analgesia was compared with a similar group of nulliparas delivered after labor epidural analgesia was available on request. The primary outcome variable was a non-occiput anterior position or malpositioned fetal head at vaginal delivery. Results The frequency of epidural use increased from 0.9% before epidural analgesia became available on demand to 82.9% afterward. Fetal head malpositioning at vaginal delivery occurred in 26 of 434 (6.0%) women delivered in the before period compared with 29 of 511 (5.7%) in the after period (relative risk 0.95, 95% confidence interval 0.6, 1.6). No statistically significant difference in the incidence of fetal head malpositioning was present after patients were stratified by mode of delivery (Mantel–Haenszel weighted relative risk 0.94, 95% confidence interval 0.6, 1.4). The study sample size provided 85% power to detect a two-fold increase in the incidence of fetal malpositioning from a baseline rate of 6% associated with on-demand epidural use. Conclusion Providing on-request labor epidural analgesia to nulliparas in spontaneous labor did not result in a clinically significant increase in the frequency of fetal head malpositioning at vaginal delivery. Providing on-request labor epidural analgesia with combined local anesthestic-narcotic to nulliparas in spontaneous labor is not associated with increased frequency of fetal head malpositioning at vaginal delivery.