Judith Rooks, CNM, MPH, a noted midwifery author and researcher, has spent countless hours campaigning to re-integrate nitrous oxide into the array of choices for pain relief in labor for American women.  Nitrous oxide was once commonly used in American hospitals, and is still a method of choice for pain relief in the U.K., both in hospital and for home births.  When epidural anesthesia began its intrusion into American labor units and with it the constant presence of an anesthesiologist or anesthetist, nitrous oxide fell out of favor and was eventually forgotten altogether.  However, it is slowly making a comeback, and Rooks has consistently responded to the arguments from the anesthesia community about its safety for laboring women and for care providers.  She worked to find a manufacturer of a safe, convenient apparatus for the delivery of nitrous oxide in the labor room, and to find midwives who would be willing to use it.  Her persistence is finally paying off.  According to an article in Family Practice News, “laughing gas” for labor pain is back.  “The RTEmagicC_z13ng0tw_95459.photo.jpgNitronox system delivers a fixed mixture of 50% oxygen and 50% nitrous oxide that is safe, effective, inexpensive, simple, and popular with many laboring women, said Judith T. Bishop, C.N.M., M.P.H. Physician supervision is not needed for its use, she added at a meeting on antepartum and intrapartum management sponsored by the University of California, San Francisco (UCSF).”

If you have experience with or are interested in having access to nitrous oxide for labor, ask your hospital or midwife if it is available – and urge them to make it available if not.

Rooks J. Safety and Risks of Nitrous Oxide Labor Analgesia:  A Review.  J Midwifery Womens Health 2011;56:557–565.


Introduction: This review of the safety and risks of nitrous oxide (N2O) labor analgesia presents results of a search for evidence of its effects
on labor, the mother, the fetus, the neonate, breastfeeding, and maternal-infant bonding. Concerns about apoptotic damage to the brains of
immature mammals exposed to high doses of N2O during late gestation, possible cardiovascular risks from hyperhomocysteinemia caused by
N2O, a hypothesis that children exposed to N2O during birth are more likely to become addicted to amphetamine drugs as adults, and possible
occupational risks for those who provide care to women using N2O/O2 labor analgesia are discussed in detail.

Methods: Research relevant to the 4 special concerns and to the effects of N2O analgesia on labor and the mother-child dyad were examined
in depth. Three recent reviews of the biologic, toxicologic, anesthetic, analgesic, and anxiolytic effects of N2O; 3 reviews of the safety of 50%
N2O/oxygen (O2) in providing analgesia in a variety of health care settings; and a 2002 systematic review ofN2O/O2 labor analgesia were used.

Results: Nitrous oxide analgesia is safe for mothers, neonates, and those who care for women during childbirth if the N2O is delivered as a 50%
blend with O2, is self-administered, and good occupational hygiene is practiced. Because of the strong correlation between dose and harm from exposure to N2O, concerns based on effects of long exposure to high anesthetic-level doses of N2O have only tenuous, hypothetical pertinence to the safety of N2O/O2 labor analgesia.

Discussion: Nitrous oxide labor analgesia is safe for the mother, fetus, and neonate and can be made safe for caregivers. It is simple to administer, does not interfere with the release and function of endogenous oxytocin, and has no adverse effects on the normal physiology and progress of labor.