Popping up on the internet from time to time are announcements that hospitals are offering nitrous oxide (N2O), a.k.a. laughing gas, as a new option for relieving labor pain. Used for dental procedures and often used for labor pain in Europe, it is regaining popularity in the U.S. Is it helpful? What are its advantages? Are there any disadvantages? Let’s look at the evidence.
Women do find N2O to be helpful. They rate pain relief effectiveness substantially higher than inhaling oxygen or no treatment (Dammer 2014; Klomp 2012). More than one-third of 1st-time mothers and half of women with prior births found N2O to be “very effective” at relieving pain, similar to the percentages who rated injected opioids as “very effective” (Likis 2014). However, similar percentages rated mental strategies “very effective” (Likis 2014), and a very small study (10 women in each group), for whatever it’s worth, reported equivalence between N2O & TENS (Klomp 2012).
N2O has some advantages over injected opioids and epidurals. It provides rapid onset of moderate pain relief that is under the laboring woman’s control. It apparently has no adverse effect on labor progress or the baby, although trials are too small even in the aggregate to detect uncommon complications in the baby (Klomp 2012). Women can’t overdose because if they breathe in too much, they start to nod off, and the hand holding the mask falls away from their face. Also, the gas clears rapidly from the system (Klomp 2012), which means that unlike epidurals or injected opioids, if a woman experiences an undesired effect, stopping use should relieve symptoms within a short time. As for what those undesired effects may be, N2O can cause nausea, dizziness, or drowsiness.
The Take-Away: N2O inhalation could be a good option if you prefer to avoid pain medication and find non-drug techniques insufficient. N2O can also be useful if you want to delay having an epidural until active labor (around 6 cm dilation), which reduces the odds of experiencing some epidural complications such as developing a fever (Lieberman 2002), or if you have to wait because the anesthesiologist isn’t available. N2O might also prove helpful if the epidural doesn’t take, which happens occasionally, or coverage is patchy.
Dammer U, Weiss C, Raabe E, et al. Introduction of Inhaled Nitrous Oxide and Oxygen for Pain Management during Labour – Evaluation of Patients’ and Midwives’ Satisfaction. Geburtshilfe Frauenheilkd 2014;74(7):656-60.