title: A randomized controlled trial of nitrous oxide for intrauterine device insertion in nulliparous women.
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 13-45years 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 (N2O/O2) through a nasal mask for 2minutes before insertion. Only the person administering the inhalation agent was aware of group assignment. The primary outcome was maximum pain assessed 2minutes 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±24.8mm for the N2O/O2group and 55.3±20.9mm for the O2group (P=0.86). Adverse effects were reported for 6 (15%) women in the N2O/O2group and 7 (18%) in the O2group (P=0.32).
  
  
  CONCLUSIONS
  N2O/O2did not reduce the pain of IUD insertion among nulliparous women. ClinicalTrials.gov: NCT02391714.
authors.affiliation: Department of Obstetrics and Gynecology, University of New Mexico School of Medicine, Albuquerque, NM, USA. Electronic address: rhsingh@salud.unm.edu.
authors.forename: Rameet H
authors.initials: RH
authors.lastname: Singh
authors.affiliation: Department of Obstetrics and Gynecology, University of New Mexico School of Medicine, Albuquerque, NM, USA.
authors.forename: Lauren
authors.initials: L
authors.lastname: Thaxton
authors.affiliation: Department of Obstetrics and Gynecology, University of New Mexico School of Medicine, Albuquerque, NM, USA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Carr
authors.affiliation: Departments of Family and Community Medicine, and Obstetrics and Gynecology, University of New Mexico School of Medicine, Albuquerque, NM, USA.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Leeman
authors.affiliation: Department of Obstetrics and Gynecology, University of New Mexico School of Medicine, Albuquerque, NM, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Schneider
authors.affiliation: Department of Obstetrics and Gynecology, University of New Mexico School of Medicine, Albuquerque, NM, USA.
authors.forename: Eve
authors.initials: E
authors.lastname: Espey
mesh_terms: D000328:Adult; D018685:Anesthetics, Inhalation / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007436:Intrauterine Devices, Medicated; D009516:New Mexico; D009609:Nitrous Oxide / Q000627:therapeutic use*; D010146:Pain / Q000209:etiology*; D059408:Pain Management / Q000379:methods*; D010147:Pain Measurement; D017060:Patient Satisfaction; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide
keywords: Insertion; Intrauterine device; Nitrous oxide; Pain