Tuesday, September 30, 2014

Nitrous Oxide in Labor: Don’t Start Laughing Quite Yet

What do Australia, Canada, Finland, Sweden and the UK all have in common? 

They all have been using nitrous oxide N2O as a labor analgesia for years.  The results have been highly effective and safe.  

Why is it just arriving in the US for use in labor?

How N2O Works
Nitrous oxide works chemically to increase the release of endogenous opioid polypeptide compounds (also known as endorphins), corticotropins and dopamine in the mother’s brain.

The Pros

  • Nitrous oxide can be administered and discontinued easily.  The effects of the nitrous oxide are completely gone within five minutes.
  • Nitrous oxide is safe to use throughout labor and the Second Stage.  Studies are showing little or no adverse effects on the progress of labor, maternal health or fetal health.
  • Nitrous oxide is self-administered  (about 30-60 seconds prior to each contraction) which allows the laboring mother to decide when and how much she uses.
  • Lower cost and less invasive than epidural anesthesia or narcotic analgesia.
  • Positioning is not limited, except by length of hose that is attached to supply source.
  • Monitoring and anesthesia related interventions (such as bladder catheterization) not necessary.
  • Does not require the presence of an anesthesiologist for administration/monitoring.

The Cons

  • Nitrous oxide may cause some minor side effects such as nausea, drowsiness and dizziness.
  • Questionable risk of repeated occupational exposure by health care providers.
  • Room ventilation systems and scavenging systems must be in place to remove waste gases.
  • Insufficient data exists that focus on women’s satisfaction, route of birth, other maternal/infant side effects and health system factors affecting use.
  • Potential for increased problems with sedation and decreased maternal blood oxygen levels if used in combination with injected narcotics.
  • Concerns exist regarding immature fetal brains exposure to high doses of N2O. Unknown effects on alertness of newborns and their ability to interact with the new environment.
  • Hypothesis exists that children exposed to N2O during birth are more likely to become addicted to amphetamine drugs as adults.

There may still be research to do before we see N2O routinely in US hospitals.  But as far as analgesia/anesthesia goes, it is the most promising so far.

Video of Blender of N2O and oxygen:


  1. ACNM Position Statement, Nitrous Oxide for Labor Analgesia.http://www.midwife.org/acnm/files/acnmlibrarydata/uploadfilename/000000000080/nitrous_oxide_12_09.pdf
  2. ACNM (2013) Nitrous Oxide for Pain Relief in Labor. Journal of Midwifery and Womens Health. 58(6): 727-728.http://onlinelibrary.wiley.com/doi/10.1111/jmwh.12103/pdf
  3. Agency for Healthcare Research and Quality Clearinghouse (2012) Nitrous Oxide for the Management of Labor Pain: Comparative Effectiveness Review Executive Summary No. 67.http://effectivehealthcare.ahrq.gov/ehc/products/260/1230/CER67_NitrousOxide_ExecutiveSummary_20120817.pdf

    Baysinger, C. American Society of Anesthesiologists: Nitrous Oxide for Labor Analgesia.https://www.asahq.org/For-Members/Clinical-Information/Nitrous-Oxide.aspx  
  4. Childbirth Connection. Labor Pain: Nitrous Oxide.http://www.childbirthconnection.org/article.asp?ck=10188
  5. Dammer, U. et al. (2014) Introduction of Inhaled Nitrous Oxide and Oxygen for Pain Management during Labour – Evaluation of Patients’ and Midwives’ Satisfaction. Geburtshilfe Frauenheilkd. 74(7): 656-660.  Free article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119100/?report=printable
  6. Rooks, J.P. (2011) Safety and risks of nitrous oxide labor analgesia: a review. Journal of Midwifery and Womens Health. Nov-Dec; 56(6): 557-65.
  7. Zuck, D. et al. (2012) Nitrous Oxide: Are you having a laugh? Royal Society of Chemistry: Education in Chemistry. March.http://www.rsc.org/images/Nitrous-oxide_tcm18-214047.pdf

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