Early versus late epidural analgesia and risk of instrumental delivery in nulliparous women: a systematic review.

OBJECTIVE Review of the literature regarding the relation between the timing of epidural analgesia and the rate of caesarean or instrumental vaginal deliveries. SEARCH STRATEGY Pubmed, Embase and the Cochrane Library were searched for articles published until 31 July 2010. SELECTION CRITERIA Studies were selected in which the effects of early latent phase (defined as a cervical dilatation of 3 cm or less) epidural analgesia (including combined-spinal epidural) and late active phase epidural analgesia on the mode of delivery in nulliparous women at 36 weeks of gestation or more were evaluated. DATA COLLECTION AND ANALYSIS Data extraction was completed by using a data-extraction form. Risk ratio and its 95% confidence intervals were calculated for caesarean delivery and instrumental vaginal delivery. Pooled data were calculated. MAIN RESULTS The search retrieved 20 relevant articles, of which six fulfilled the selection criteria of inclusion. These six studies reported on 15,399 nulliparous women in spontaneous or induced labour with a request for analgesia. Risk of caesarean delivery (pooled risk ratio 1.02, 95% CI 0.96-1.08) or instrumental vaginal delivery (pooled risk ratio 0.96, 95% CI 0.89-1.05) was not significantly different between groups. AUTHORS' CONCLUSIONS This systematic review showed no increased risk of caesarean delivery or instrumental vaginal delivery for women receiving early epidural analgesia at cervical dilatation of 3 m or less in comparison with late epidural analgesia.