There have been some (though not enough) studies performed by researchers of laboring women’s use of Nitrous Oxide (N2O) as an analgesic during childbirth.

Nitrous Oxide (also known as “laughing gas”) is an odorless, nonflammable, and tasteless gas that provides Pain Relief. By inhaling a 50% nitrous oxide and 50% oxygen mixture through a face mask, a laboring woman experiences some (not total) pain relief. The laboring woman holds the mask in her hand and inhales the gas either just before or during the contraction to take the edge off of the pain at the peak of the contraction.  (Best pain relief seems to come when a woman can time it so that she begins breathing in the gas 30 seconds before the start of her next uterine contraction.)

Please keep in mind that these advantages and disadvantages apply solely to intermittent, not continuous, use of Nitrous Oxide during childbirth. The presumption is that a woman would use the gas during a contraction and then remove the mask from her face in between contractions.

ADVANTAGES OF INTERMITTENT NITROUS OXIDE USE IN LABOR:

• It decreases anxiety in some women.
• It is noninvasive (unlike other available pain relief drugs offered to birthing women).
• The laboring mom is in complete control of its use, and can choose to start its use or stop its use at any time.
• It does not impair a laboring mom’s movements – she can use Nitrous Oxide in a variety of locations and positions.
• The effects of the gas wear off in minutes.
• There are currently no known side effects on the newborn from what has been observed after the baby’s birth (unlike other labor pain relief drugs).

DISADVANTAGES OF NITROUS OXIDE USE IN LABOR:

• Some women have increased feelings of nausea (although there was not an increased incidence of vomiting associated with Nitrous Oxide use during childbirth)
• Some women experience vertigo.
• Some women feel claustrophobic (because of using a face mask to breathe in the Nitrous Oxide gas).
• Some women find it distracting to establish her breathing rhythm while using the Nitrous Oxide.
• Fatigue sets in when used for prolonged periods of time.
• It does not provide total pain relief (more like, it takes the edge off).

SAFETY:

Nitrous Oxide has been available as an option for pain relief during childbirth in the United Kingdom since 1933, when it became widely distributed. In fact, “The use of [Nitrous Oxide] as a labor analgesic in the United Kingdom has produced a long track record of safe outcomes for both mother and child.” (p. e128)

However, recent studies of labor analgesics, including Nitrous Oxide, that have been performed on rodents and primates have suggested that these drugs may have a negative impact on the fetal brain, possibly inducing apoptotic changes if exposed to the drugs either in utero or shortly after birth. (Apoptosis is a process of cell self-termination within the body—and in this case, some component in the analgesics is causing these fetal brain cells to self-destruct.)

Though small concentrations of Nitrous Oxide exposure over a short period of time has imperceptible long-term effect on a newborn, it may be wise to keep in mind that “high concentrations for prolonged periods may be deleterious.” (p. e128)

As with any drug taken or intervention given during pregnancy, childbirth, or while breastfeeding, it is good to remember that there are always risks and benefits to be weighed. As of yet, the FDA has not recommended a shift in the use of anesthetics for either children or fetuses, but “the precise effects on brain development in human fetuses exposed to N2O or other anesthetic agents in utero remain largely unknown.” (p. e128)

Among all the options available to women hoping to avoid intervention but still seeking some pain relief, it seems that Nitrous Oxide may be a laboring woman’s best bet for some measure of pain relief in childbirth while experiencing the least negative impact for her and her newborn.

This article is a summary of an excellent review of Nitrous Oxide use in labor entitled “Nitrous Oxide for Labor Analgesia: Expanding Analgesic Options for Women in the United States”( by Michelle R. Collins, PhD CNM; Sarah A. Starr, MD; Judith T. Bishop, MSN, CNM; and Curtis L. Baysinger, MD) and originally published in Vol. 5 No. 3/4 of Reviews in Obstetrics & Gynecology in 2012. Read the full text online here (as of December 8, 2015): http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3594866/