title: Nitrous oxide for the management of labor pain: a systematic review.
abstract: BACKGROUND
  We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management.
  
  
  METHODS
  We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate.
  
  
  RESULTS
  We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited.
  
  
  CONCLUSIONS
  The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.
authors.affiliation: From the *Vanderbilt Evidence-based Practice Center, Institute for Medicine and Public Health, Vanderbilt University Medical Center; †Department of Medicine, Vanderbilt University Medical Center; ‡Department of Obstetrics and Gynecology, Vanderbilt University Medical Center; §Vanderbilt University School of Nursing; ‖Division of Obstetric Anesthesiology, Department of Anesthesiology, Vanderbilt University Medical Center; ¶Eskind Biomedical Library, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Frances E
authors.initials: FE
authors.lastname: Likis
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Andrews
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Collins
authors.forename: Rashonda M
authors.initials: RM
authors.lastname: Lewis
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Seroogy
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Starr
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Walden
authors.forename: Melissa L
authors.initials: ML
authors.lastname: McPheeters
mesh_terms: D016362:Analgesia, Obstetrical / Q000379:methods; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D001034:Apgar Score; D002986:Clinical Trials as Topic / Q000379:methods; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D048949:Labor Pain / Q000188:drug therapy* / Q000453:epidemiology; D009609:Nitrous Oxide / Q000008:administration & dosage*; D059408:Pain Management / Q000379:methods*; D011247:Pregnancy
chemical_list: D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide