A Cochrane overview included 15 Cochrane reviews (255 included trials) and 3 non-Cochrane reviews (55 included trials) of pain management in labour. Inhaled analgesia was compared with placebo or no treatment in 9 studies involving a total of 1495 women. Significantly fewer women in the inhaled analgesia group experienced severe pain compared with placebo or no treatment (RR 0.06, 95% CI 0.01 to 0.34; 2 trials, n=310). Pain intensity during the first stage of labour was significantly lower in the inhaled analgesia group (MD -3.50, 95% CI -3.75 to -3.25; 1 trial, n=509). There was no difference in assisted vaginal births (RR 1.50, 95% CI 0.44 to 5.15; 1 trial, n=200) or in caesarean sections (RR 1.20, 95% CI 0.75 to 1.91; 3 trials, n=465). Women receiving inhaled analgesia were more likely to experience vomiting (RR 9.05, 95% CI 1.18 to 69,32; 2 trials, n=619), nausea (RR 43.10, 95% CI 2.63 to 706.74; 1 trial, n=509), and dizziness (RR 113.98, 95% CI 7.09 to 1833.69; 1 trial, n=509). Flurane was more effective than nitrous oxide for pain relief (MD 13.87, 95% CI 4.02 to 23.72; 3 trials, n=123). However, there was no significant difference between nitrous oxid vs flurane in satisfaction with pain relief during the second stage of labour (proportion with good or excellent pain relief; RR 0.89, 95% CI 0.78 to 1.01; 4 trials, n=323).
Date of latest search: 31 October 2011