A double-blind, randomized controlled trial on the use of a 50:50 mixture of nitrous oxide/oxygen in pain relief during suction evacuation for the first trimester pregnancy termination.

Background: This prospective study assessed the role of a 50:50 mixture of nitrous oxide (N2O) and oxygen for pain relief during the termination of first trimester pregnancies by suction evacuation under conscious sedation.

Methods: Ninety women undergoing suction evacuation up to 12 weeks of gestation were randomized by a computer-generated randomization list and allocated using sealed envelopes to receive the N2O/O2 mixture or air during the operation. Pain scores during and after suction evacuation, post-operative side effects and satisfaction level were compared.

Results: No statistically significant differences in pain scores, post-operative side effects and satisfaction levels were found between the two groups.

Conclusions: N2O/O2 did not reduce the pain level during suction evacuation for the first trimester pregnancy termination under conscious sedation.