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Is It Safe to Work Around Nitrous Oxide While Pregnant?

I am 24 weeks pregnant and wondering if there are any risks to working around nitrous oxide in the dental setting.

QUESTION: I am 24 weeks pregnant and wondering if there are any risks to working around nitrous oxide in the dental setting.

ANSWER: Over the past several decades, researchers have been studying some of the harmful agents used in dental offices and how they may affect reproductive and pregnancy outcomes. Research has focused mainly on mercury and nitrous oxide, as well as certain sterilizing agents, such as ethylene oxide. The evidence investigating a relationship between mercury and ethylene oxide exposure and adverse pregnancy outcomes and infertility is inconclusive. Research does show, however, a connection between nitrous oxide and adverse pregnancy and fertility outcomes.

Sandra Olfert, PhD, authored the literature review on this topic titled “Reproductive Outcomes Among Dental Personnel: A Review of
Selected Exposures” in 2006.1 She concludes, “There is some evidence to support a direct link between exposure to nitrous oxide and spontaneous abortion and infertility; however, this evidence is limited.” Here are some important points from the literature review:

  • Anesthetic gasses, such as nitrous oxide, slow the rate of cell division and increase the rate of abnormal cell formation.
  • Nitrous oxide oxidizes vitamin B12 and impairs synthesis of thionine, folate, and thiamine.
  • The amount of exposure to nitrous oxide in dental offices is small, but exposure is continuous and chronic. Thus, it may be more dangerous than short-term exposure to high concentrations.

Even though these points are alarming, the review points out other considerations:

  • Most of the studies investigating the effects of nitrous oxide on pregnancy outcomes are older (conducted in the mid-1990s) and were done before
    scavenging was widely used in dental offices.
  • None of the studies included ambient gas sampling. In other words, there may have been other contributing airborne factors that led to adverse outcomes.
  • Few studies examined nitrous oxide effects on only dental office workers; most included nurses, anesthetists, and other medical personnel.
  • Most of the data in the studies were collected by questionnaire, leaving the reporting subjective and open to misinterpretation.

What does this mean to pregnant dental hygienists who work in offices where nitrous oxide is used? It likely means that avoiding nitrous oxide, no matter how limited the exposure may be, is the most prudent course of action. More studies—conducted only in dental offices with current standards of scavenging and equipment—are needed to show if there truly is an association between nitrous oxide exposure and adverse reproductive and pregnancy events. Until then, take precautions to protect yourself and your unborn child.


1. Olfert S. Reproductive outcomes among dental personnel: a review of selected exposures. J Can Dent Assoc. 2006;72(9):821—825.

The Ask the Expert column features answers to your most pressing clinical questions provided by Dimensions of Dental Hygiene’s online panel of key opinion leaders, including: Jacqueline J. Freudenthal, RDH, MHE, on anesthesia; Nancy K. Mann, RDH, MSEd, on cultural competency; Claudia Turcotte, CDA, RDH, MSDH, MSOSH, on ergonomics; Van B. Haywood, DMD, and Erin S. Boyleston, RDH, MS, on esthetic dentistry; Michele Carr, RDH, MA, and Rachel Kearney, RDH, MS, on ethics and risk management; Durinda Mattana, RDH, MS, on fluoride use; Kandis V. Garland, RDH, MS, on infection control; Mary Kaye Scaramucci, RDH, MS, on instrument sharpening; Stacy A. Matsuda, RDH, BS, MS, on instrumentation; Karen Davis, RDH, BSDH, on insurance coding; Cynthia Stegeman, EdD, RDH, RD, LD, CDE, on nutrition; Olga A.C. Ibsen, RDH, MS, on oral pathology; Jessica Y. Lee, DDS, MPH, PhD, on pediatric dentistry; Bryan J. Frantz, DMD, MS, and Timothy J. Hempton, DDS, on periodontal therapy; Ann Eshenaur Spolarich, RDH, PhD, on pharmacology; and Caren M. Barnes, RDH, MS, on polishing. Log on to to submit your question.

From Dimensions of Dental Hygiene. November 2011; 9(11): 90.

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