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Nitrous Oxide – the “other” pain relief option

by Dr. EeVon Ling, ND

** At the time of this writing, COVID-19 policies have restricted the use of nitrous oxide in some birth settings. Inquire with your birth location if this option is available to you. 

What is it? 

Laughing Gas for pain relief?

Nitrous oxide (N2O). Aka “Laughing Gas”, “Gas”, “Nitrous”, “Entonox” (Brand name). 

It is a colourless and nearly odourless gas that is a chemical compound and mixture of nitrogen and oxygen. It has both analgesic and anesthetic properties – meaning it can reduce or alter pain sensation and pain perception.  You may know about nitrous oxide because of its wide use in dentistry. It is the same gas, but the concentration used during labour is much less. 

I haven’t heard much about Nitrous Oxide. Is it common in labour? 

You may be surprised to learn that N2O is the most commonly used form of analgesia in childbirth around the world. 

Historically, N2O has been in use for more than a hundred years! It was widely used in US hospitals for childbirth in the 1930’s – 1950’s. By the 1960’s, epidural use sharply overtook as the primary choice for pain relief and N20 use would pretty much disappear from labour and delivery in the US. But more recently in Canada, its popularity has increased as a pain relief option.  A survey in 2006 found that about 1 in 5, or 20%, of women who gave birth in Ontario used N2O for pain relief. In comparison, the rate of epidural use is about 50-60%. 

Is it as good as using an epidural for pain relief?  

The short answer is “no”. 

It does not replace getting an epidural in terms of pain relief. An epidural is meant to completely take away pain to the point where you usually don’t even know when you are having a contraction or not. Because N2O doesn’t take away pain like an epidural, I have noticed that OB’s and nurses don’t mention it as an option to clients, even to clients that express that they want to labour without an epidural. They don’t consider the value it may offer and in fact, I’ve heard OB’s tell my clients that nitrous oxide “does nothing”. This thinking is a result of comparing N2O with an epidural, but it is a great disservice to completely dismiss it as a useful coping tool.

The more thoughtful answer is that nitrous oxide is a “good enough pain relief”. The following are quotes from my own clients who used nitrous oxide as their main pain relief: 

“It helped take the edge off”

“It helped take the edge off” 

“It made me care less about the pain”

“Breathing through the tube helped distract me” 

“It helped me relax more and focus” 

“It helped me birth without an epidural”

“Without it, I would not have been able to have my homebirth”

“I think it made me a little giddy”**

In some cases, clients have used N2O while waiting to get an epidural or when they are receiving stitches on their perineum post birth. 

What can I expect if I use N2O? 

Begin use at the beginning of a contraction

Where available, it is used in a hospital or birth centre setting, and occasionally some midwife groups have it available for home births (check with your midwife or birth location for availability). It is administered through a tube with a face mask attached. When you are in labour, you hold the mask to your face and deeply breathe in the N2O at the very beginning of or in anticipation of a contraction. The maximum concentration is reached within 60 seconds so you continue to breathe the N2O gas until the contraction ends. Once the contraction is over you take the mask off of your face. Repeat this for each contraction if you continue to use it. If you’ve learned breathing exercises for labour (which I highly recommend that you do, either through a comprehensive prenatal program, HypnoBirthing or through our own Confident Birth Prenatal program), the deep breathing that you’ve been practicing is perfect for using with N2O. 

It is quick acting with the effects felt almost immediately. As described above, N2O does have the ability to alter the way you perceive and feel pain. It doesn’t take away pain like an epidural, but it can help increase your ability to cope with it. 

At the biochemical level, N2O alters levels of certain brain chemicals. It reduces those neurochemicals that activate pain (N-methyl-D-aspartate, NMDA for short) and increases neurochemicals that increase endorphins and make us feel good (dopamine, norepinephrine, endogenous opioids). It has the ability to produce a sense of euphoria and occasionally psychedelic effects. (**Yes, I’ve observed a couple clients get a little “high” while using N2O, all to their benefit)

You are able to remain alert and have full control of your body (no numbing effects). You don’t need an IV or continuous fetal monitoring, you can move freely and use the washroom, and you can eat and drink as normal. 

If you don’t think the N2O is helpful, or if you start to feel drowsy or dizzy, you simply stop using it and it leaves the body within 30 seconds.  Being able to fully control how and when you use N2O is seen as a big benefit to using this option. 

Studies of thousands of people who used N2O during labour (compared to placebo) report 

N2O helps by increasing endorphins
  • Decrease in pain perception
  • Decreased anxiety
  • Increased sense of control
  • Increased satisfaction

That said, when compared to epidural use, women were much less likely to rate N2O as effective pain management compared to those who used an epidural. But when compared with no pain relief or placebo, there was better pain relief reported with N2O use. Reported levels of satisfaction were about the same among epidural users and N2O users. And most N2O users said they would have used it again. Again, highlighting that N2O doesn’t replace using an epidural, but it may still be a very useful measure for those who want to birth without an epidural. 

Is it safe for my baby? What are the side effects? 

Some nitrous oxide does cross the placenta, however, it is safe for both you and baby when used in labour in a full-term pregnancy. It is not recommended in preterm labour as there is increased risk of brain hemorrhage for the preemie baby. Care providers may recommend using N2O only when you are in active labour (cervix is dilated 6cm or more) to reduce excess exposure to the gas. 

N2O is safe for baby when used in active labour

Otherwise, the use of N2O has not been found to affect APGAR scores in babies (the initial assessment of well-being for the newborn) and does not slow down labour or increase risks (such as interventions or c-sections) for the pregnant parent. That said, no long term studies of nitrous oxide on both the parent or baby have been conducted (in fact, no long term studies of many interventions in birth exist). From a biochemical point of view, N2O exposure can decrease levels of vitamin B12. Vitamin B12 is an essential nutrient for blood, nervous system and metabolic functions. It is found in animal-based foods such as meat, eggs and usually included in prenatal vitamins. If levels of vitamin B12 is a concern, this is something that can be addressed post birth with your naturopathic doctor. 

Potential side effects (from most common): 

  • Nausea 
  • Vomiting
  • Dizziness
  • Drowsy
  • Reduced sense of awareness
  • Reduce feelings of being present; Increases feeling detached from situation 
  • “Mask phobia” from using the mask on their face

Bottom-line: 

Nitrous oxide, if available, can be helpful during labour. It can be used as your main coping strategy (along with massage, relaxation exercises and breathing techniques) or be a helpful tool as you wait for an epidural or even be used immediately post birth if you need to receive stitches for your perineum. 

We at Your Downtown Doula are fully supportive of your choices in birth. We act as your source of information so that you are fully aware of the options so that you can make good decisions for yourself and your baby in labour. We have attended births where parents chose N2O, epidurals or other means to cope and in the end, positive births can happen no matter how you decide to journey towards parenthood. 

Want to learn more about how a doula can be a valuable support to you during pregnancy, labour, childbirth and beyond? Book a free 15 min meet and greet with one of our Naturopathic doctors and doulas today! 

Dr. EeVon Ling, ND

Resources: 

https://www.contemporaryobgyn.net/view/nitrous-oxides-revival-childbirth

https://evidencebasedbirth.com/nitrous-oxide-during-labor/

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