Fellow American preggos, we are being deprived and we didn’t even know it!

In that inevitable conversation of whether or not we are going to want pain medication during our labor and delivery, the only option that really comes to mind is the epidural.

But for most women across the world, the epidural is not the only analgesic pain relief option.  WHAT!?

Our fun times Saturday activity a few weeks ago was an all-day birth class.  Pretty typical stuff, lots of vaginas and babies trying to fit through spaces that seem impossible to navigate.  But one issue that came up, almost in passing, really stood out to me.  A fellow student asked the instructor about the “gas option” for pain relief.  Pretty sure every woman in the room leaned in with a very confused look on her face – thinking, what the hell is “the gas option”?

As explained by our instructor, the question referred to nitrous oxide.  And, no, the gas option was not available at our hospital nor was it available at >99.99% of the hospitals in this country.  Fortunately for us, here in the Bay Area, if this is something we really wanted, we could just go across the bridge to UCSF, one of the FIVE hospitals in the US that offers this option to laboring mothers.  Going across the Bay Bridge while in labor is not my idea of fun so I’ll forgo this opportunity, but I was intrigued.

Apparently, nitrous oxide (N₂O, also known as “laughing gas”) is the most commonly used labor analgesic in the world – used by more than 60% of laboring women in the UK, 70% in Sweden!

First, how does it work?  It seems that the best “dose” of N₂O is a 50:50 mix of nitrogen and oxygen, mixed immediately prior to inhalation.  It is self-administered – the woman holds up the mask and takes a puff any time she wants.  How it works, physiologically, is a bit murkier but the overall gist is that it effects the way pain is perceived in the brain. It is very temporary – it takes about 30 seconds to have an effect and it is cleared from the system within minutes.  It does not accumulate, it only goes through the lungs and never involves the liver so there are no bits left over from metabolism.

So how good is nitrous oxide for pain relief during labor and why is it not available to most of us here in the US?

A 2002 review by Dr. Mark Rosen, an obstetrician at UCSF, pointed out the basics of the benefits and the absurdity of the concerns [1].  In the review, he evaluated every scrap of scientific and clinical evidence he could find about the use and the study of nitrous oxide in labor pain management. Overall, what he found was that the literature was lacking.
(A more recent review demonstrates that this lack of information and sound, well-controlled studies is still a problem [2].  But I can imagine it is pretty difficult to ethically give a woman in labor a placebo pain medication, so designing that perfectly controlled experiment can be a bit tricky.)

With that said, there were some key points that Rosen could assert.  First, the concerns are stupid (my words, not his).  For the actual labor component, there is far less to worry about than pretty much any other medical option – N₂O does not affect uterine contractions and it does not affect the newborn.  It can cause drowsiness – but the beauty of the self-administered system is that if the woman gets drowsy or starts to pass out, she drops the masks, inhales fresh air and, voila! drowsiness from the N₂O is gone.  The main concerns really center around the gas getting out into the room and into the world.  Escape into the room exposes the health care workers BUT most of our hospitals these days have pretty damn good ventilation systems and the units for administering the N₂O have scavenging systems in place to grab the escaped gas before it accumulates.  Plus, the mask only releases N₂O when the patient takes a pull.  The second escape concern is that N₂O is a potent greenhouse gas.  But as Judith Rooks points out in her 2007 article in the Journal of Midwifery & Women’s Health [3] “…it is clear that medical uses of N₂O are a very small part of the problem. In summary, the global warming risks are valid but low relative to many less vital uses of N₂O, including NASCAR races, the followers of which, however, have a more effective political voice than pregnant women in the United States, who might want to use N₂O but who don’t even know about it as an option”.  Sing it, Judith!

Second, for the pain, well, let’s just say it’s no epidural.  According to Rosen, it has not been shown to be a potent labor analgesic, it does not eliminate pain, but it can provide “a sense of relief”.  And there are ways to improve the effectiveness of the pain relief; for example, learning how to time inhalation with contractions since it can take up to 30 seconds to kick in and does not last long after the mask is removed.  But, it is safe and it is adequate and most women who labor with access to N₂O do not end up going for the stronger stuff.

As someone who studies stress, I am reminded of a classic stress experiment involving two rats, two tethered cages, two electrified floors, and one off lever to push. The electrified floor switches on unexpectedly, give both rats a little shock, and one of the rats has the ability to stop this pain by hitting the lever in its cage.  Same shock, same timing, same pain, but one rat has a sense of control over this pain and the other does not.  It is this sense of control that appears to be what saves this rat from the stress of the situation while the other rat turns into a stressed out mess (non-scientific terminology, of course).

By giving a laboring woman the option, the mask to hold in her hand to self-administer a little hit of possible pain relief, we are giving her control. We are lowering the stress of the situation. Why? WHY? Is this option not widely available or even known about in the US? The birth class instructor seems to think that it has something to do with money – no one makes money from an off-patent, inexpensive, old school gas option so who is going to promote it?  If this is actually the case, it would be another incredibly sad and f-ed up thing about the American Health Care System.

Personally, I am going to try to get through as much of labor as physically possible without medication.  I’m honestly curious about what it all feels like (all the mamas out there have one eyebrow raised with deep insight and skepticism).  But, man, I do wish I had the option of hitting some laughing gas rather than only having the option that involves a tube feeding nerve knockout juice past my spinal column.

1. Rosen MA. (2002) Nitrous oxide for relief of labor pain: A systematic review. Am J Obstet Gynecol;186(Suppl 5):S131–59.

2. Likis FE, Andrews JA, Collins MR, et al. (2012) Nitrous oxide for the management of labor pain. Comparative effectiveness review no. 67. AHRQ publication no. 12- EHC071-EF. Rockville (MD): Agency for Healthcare Research and Quality.

3. Rooks, J. P. (2007) Use of Nitrous oxide in Midwifery Practice – Complementary, Synergistic, and Needed in the United States. Journal of Midwifery & Women’s Health; 52 (3): 186-189.