Six studies met the inclusion criteria, of which 2 were RCTs. The total number of participants was 3,022 (1,699 epidural and 1,323 non-epidural). Two studies were also identified as RCTs, but were not included in the meta-analyses as the control groups had also received epidural analgesia during the first stage of labour.
The pooled rate of Caesarean delivery was significantly higher in women receiving epidural analgesia with a risk difference (i.e. difference in rates) of 10.3% (95% confidence interval, CI: 8.2, 12.5); the risk difference for RCTs only was 14.6% (95% CI: 5.4, 23.8). The random-effects risk difference was not significant (p=0.08), though no summary information is presented on risks calculated by this method.
For studies of Caesarean deliveries for dystocia, the Caesarean delivery rate was higher in the epidural group with a pooled risk difference of 9.1% (95% CI: 6.7, 11.5), and a pooled risk for RCTs only of 12.3% (95% CI: 4.3, 20.3).
For studies of Caesarean delivery for foetal distress, the pooled risk difference was 0.7% and not significant. No other summary figures were given for this subgroup.
A subgroup analysis was also carried out for the patients who received oxytoxin in one included study. Use of oxytoxin and use of epidurals were significantly associated (p<0.05). There was a non significant increase of 1.4% in the Caesarean rate in the epidural group receiving oxytoxin.
Results were also stratified according to whether the patients were private or clinic patients; a 4% and 1% increase in Caesarean rates was shown for private and clinic patients, respectively, representing a relative risk of 1.2 in both groups (not significant). However, the underlying Caesarean rates were different for private and clinic patients overall: 17.1 and 5.2% respectively (p<0.05). For patients receiving oxytoxin the disparity was larger: 27.1 versus 5.3% respectively (p<0.05).