Use of Nitrous Oxide in Labor and Possible Interaction with Systemic Opioids or Sedatives/Hypnotics

  • July 2021

(Reaffirmed October 2022)

This Practice Advisory was developed by the American College of Obstetricians and Gynecologists' Committee on Clinical Practice Guidelines—Obstetrics in collaboration with Kathleen Brookfield, MD, PhD, MPH; Manisha Gandhi, MD; Anjali J. Kaimal, MD, MAS; and Megan McReynolds.

The use of nitrous oxide (N2O) in labor is addressed in Practice Bulletin No. 209, “Obstetric Analgesia and Anesthesia” 1 . In the Practice Bulletin, it is described that nitrous oxide can be used safely with other forms of analgesia. However, a statement from the American Society of Anesthesiologists noted that in the setting of nitrous oxide analgesia, the addition of systemic opioids or sedatives/hypnotics may lead to deeper levels of sedation and increase the risk of respiratory depression and associated maternal hypoxemic episodes 2 . As a result, if a combination of opioids or sedatives/hypnotics with nitrous oxide is used for labor analgesia, there may be increased risk of adverse events.

Based on this concern for potential maternal adverse consequences, co-administration of systemic opioids or sedatives/hypnotics and inhaled nitrous oxide for labor analgesia is not recommended.


  1. Obstetric analgesia and anesthesia. ACOG Practice Bulletin No. 209. American College of Obstetricians and Gynecologists. Obstet Gynecol 2019;133:e208-25. doi: 10.1097/AOG.0000000000003132.
    Article Locations:
    Article Location
  2. Rollins MD, Arendt KW, Carvalho B, Vallejo M, Zakowski M. Nitrous oxide. Accessed July 21, 2021. Available at:
    Article Locations:
    Article Location

A Practice Advisory is a brief, focused statement issued to communicate a change in ACOG guidance or information on an emergent clinical issue (e.g., clinical study, scientific report, draft regulation). A Practice Advisory constitutes ACOG clinical guidance and is issued only online. Practice Advisories are reviewed periodically for reaffirmation, revision, withdrawal or incorporation into other ACOG guidelines.

This information is designed as an educational resource to aid clinicians in providing obstetric and gynecologic care, and use of this information is voluntary. This information should not be considered as inclusive of all proper treatments or methods of care or as a statement of the standard of care. It is not intended to substitute for the independent professional judgment of the treating clinician. Variations in practice may be warranted when, in the reasonable judgment of the treating clinician, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology. The American College of Obstetricians and Gynecologists reviews its publications regularly; however, its publications may not reflect the most recent evidence. Any updates to this document can be found on or by calling the ACOG Resource Center.

While ACOG makes every effort to present accurate and reliable information, this publication is provided “as is” without any warranty of accuracy, reliability, or otherwise, either express or implied. ACOG does not guarantee, warrant, or endorse the products or services of any firm, organization, or person. Neither ACOG nor its officers, directors, members, employees, or agents will be liable for any loss, damage, or claim with respect to any liabilities, including direct, special, indirect, or consequential damages, incurred in connection with this publication or reliance on the information presented.

Publications of the American College of Obstetrician and Gynecologists are protected by copyright and all rights are reserved. The College's publications may not be reproduced in any form or by any means without written permission from the copyright owner.

The American College of Obstetricians and Gynecologists (ACOG), is the nation's leading group of physicians providing health care for women. As a private, voluntary, nonprofit membership organization of more than 58,000 members, ACOG strongly advocates for quality health care for women, maintains the highest standards of clinical practice and continuing education of its members, promotes patient education, and increases awareness among its members and the public of the changing issues facing women's health care.