Hi Julia, thanks for drawing our attention to this! No, we didn’t look into it. From a quick review of the evidence, the effectiveness appears variable and uncertain. But as you rightly point out, it doesn’t require an anaesthetist, and it could therefore play an important role in a low resource setting.
To me “Inhaled analgesia appears to be effective in reducing pain intensity and in giving pain relief in labour” sounds like a ringing endorsement from Cochrane given that their usual bottom line seems to be “not enough evidence.” Just about anything for childbirth pain seems to be pretty hit-or-miss, so the fact that it’s not that effective for some people seems like not that big of a downside compared to other methods or no method.
Yes, good point! Based on the Cochrane review, we could confidently say nitrous oxide has an effect on pain. I should have said the evidence for the degree of pain relief appears variable and uncertain, although on a closer look, Cochrane’s estimate suggests 3.5 on a 0-10 scale vs placebo (which is pretty great).