(HealthDay News) – For women in labor, inhaled analgesia provides pain relief but is associated with considerable side effects, according to a study published online Sept 12 in The Cochrane Library.

Trudy Klomp, from the VU University Medical Center in Amsterdam, and colleagues conducted a systematic review of the literature to identify randomized controlled trials comparing inhaled analgesia with other inhaled analgesia, placebo, no treatment, or other methods of non-pharmacological pain management in labor. A total of 26 studies involving 2,959 randomized women were included. The Visual Analogue Scale was used to measure pain relief.

The researchers found that flurane derivatives offered better pain relief than nitrous oxide in the first stage of labor, with lower pain intensity and higher pain relief, although there was considerable heterogeneity in the analysis of pain intensity and pain relief. The nitrous-oxide group had more nausea than the flurane-derivatives group (risk ratio (RR), 6.60 two studies, 98 women). Less pain relief was reported with placebo or no treatment compared to nitrous oxide (average RR, 0.06; two studies, 310 women), but there were significantly more side effects with nitrous oxide, including nausea, vomiting, and drowsiness. There were no significant differences for any outcomes between the different strengths of inhaled analgesia, for different delivery systems, or when comparing analgesia with transcutaneous electrical nerve stimulation.

“It was found that inhaled analgesia may help relieve pain during labor but women have to be informed about the side effects, such as nausea, vomiting, dizziness, and drowsiness,” the authors write.

Full Text (subscription or payment may be required)