A randomized controlled trial of nitrous oxide for intrauterine device insertion in nulliparous women. Issue 2 (November 2016) - Singh, Rameet H.
Abstract: Objective: To evaluate the effectiveness of inhaled nitrous oxide for pain management among nulliparous women undergoing intrauterine device (IUD) insertion. Methods: A double‐blind, randomized controlled trial was conducted among nulliparous women aged 13–45 years who underwent IUD insertion at a US center between October 1, 2013, and August 31, 2014. Using a computer‐generated randomization sequence, participants were randomly assigned to inhale either oxygen (O2 ) or a mixture of 50% nitrous oxide and 50% oxygen (N2 O/O2 ) through a nasal mask for 2 minutes before insertion. Only the person administering the inhalation agent was aware of group assignment. The primary outcome was maximum pain assessed 2 minutes after insertion via a 100‐mm visual analog scale. Analyses were by intention to treat. Results: Forty women were assigned to each group. Mean maximum pain score at the time of insertion was 54.3 ± 24.8 mm for the N2 O/O2 group and 55.3 ± 20.9 mm for the O2 group ( P = 0.86). Adverse effects were reported for 6 (15%) women in the N2 O/O2 group and 7 (18%) in the O2 group ( P = 0.32). Conclusion: N2 O/O2 did not reduce the pain of IUD insertion among nulliparous women. ClinicalTrials.gov: NCT02391714