Effect of epidural analgesia on fetal head malpositioning at vaginal delivery

Abstract

Objective: To determine if nulliparous women receiving labor epidural analgesia (LEA) with combined local anesthetic/narcotic infusions are more likely to have malpositioning of the fetal vertex at delivery when compared with women not receiving epidural analgesia.Study design: Retrospective cohort analysis of nulliparous women with spontaneous labor delivered during a 12-month period immediately before the availability of on-demand LEA (Before group), and a similar group of nulliparas delivered during the 12 months after LEA was available on request (After group). The primary outcome variable was a nonocciput anterior position of the fetal head at vaginal delivery.Results: The frequency of LEA increased from 1.2% in the Before period to 83.6% in the After period. Fetal head malpositioning (occiput transverse or posterior position) at vaginal delivery occurred in 29 of 422 (6.9%) women delivered in the Before period, compared with 21 of 346 (6.1%) in the After period (P = NS). There was no statistically significant difference in the incidence of fetal head malpositioning between the Before and After periods after patients were stratified according to mode of delivery (Mantel–Haenszel weighted relative risk = 0.94, 95% CI 0.6–1.4). The sample size was sufficient to exclude a doubling in the incidence of fetal head malpositioning associated with on-request labor epidural analgesia.Conclusions: Providing on-request labor epidural analgesia with combined local anesthetic/narcotic to nulliparous women in spontaneous labor does not result in a clinically significant increase in the frequency of fetal head malpositioning at vaginal delivery.