Seven trials (n=2,962) were included.
All studies had adequate allocation concealment. The treatment groups were similar at baseline and intention-to-treat analyses were performed. None of the studies used blinding.
Epidural analgesia was not associated with any statistically significant increased risk of Caesarean section (OR 1.03, 95% CI: 0.71, 1.48). Significant statistical heterogeneity was found. When one small trial with a greatly increased section rate was eliminated from the analysis, the heterogeneity was resolved and the OR changed only slightly. The overall result, however, remained not statistically significant (OR 1.01, 95% CI: 0.80, 1.28).
There was an increased risk of instrumental vaginal delivery with epidural analgesia, although this did not reach statistical significance (OR 2.11, 95% CI: 0.95, 4.65). After excluding data from women with induced labour and those who had elective forceps delivery, the risk was higher but not significantly higher (OR 2.11, 95% CI: 0.96, 4.65).
Epidural analgesia was associated with a statistically significant increased risk of operative delivery (OR 1.63, 95% CI: 1.09, 2.42). A lower risk was obtained when two trials that used elective forceps deliveries and forceps deliveries for training purposes were excluded from the analysis.
Epidural analgesia was associated with a statistically significantly longer second stage of labour (WMD 15.2 minutes, 95% CI: 2.1, 28.2).
Significantly fewer women randomised to epidural changed to parenteral opioids than did women from opioids to epidural (OR 0.1, 95% CI: 0.5 to 0.22).
No statistically significant differences in neonatal outcomes were found between treatments. Epidural analgesia was associated with fewer neonates with Apgar scores of less than 7 (4 RCTs; OR 0.72, 95% CI: 0.26, 2.04) and an umbilical pH of less than 7.2 (3 RCTs; OR 0.72, 95% CI: 0.40, 1.27) in comparison with parenteral opioids, but these differences were not statistically significant.