Carbon dioxide versus normal saline as distension medium for diagnostic hysteroscopy: a systematic review and meta-analysis of randomized controlled trials

A meta-analysis from the available moderate quality trials suggests that NS might be superior to CO2 for use in diagnostic hysteroscopy. Owing to problems of clinical diversity, statistical heterogeneity, and risk of bias, it is clear that additional pragmatic multicenter RCTs are needed to corroborate these findings before firm evidence-based guidelines can be given.