Using Gas During Labour – Pros and Cons

Using Gas During Labour - Pros and Cons

Gas During Labour

Gas (nitrous oxide) was first discovered in 1772.

While scientists discovered its ability to alter pain perception, it became known as ‘laughing gas’ and was primarily used for recreation at carnivals and curiousity shows.

People would pay to inhale the gas for a minute, then laugh and act silly, entertaining onlookers.

It wasn’t until the 1930s that a device was developed, allowing women to use nitrous oxide during labour for pain relief, without becoming unconscious.

From then onwards, nitrous oxide became more popular for pain relief than for entertainment purposes.

Nitrous oxide is a breathable anaesthetic. It’s combined with oxygen, which gives it the name ‘gas and air’, commonly used by hospital midwives. It’s also widely used by dentists for non-surgical, out-of-hospital procedures as a numbing agent.

Most people see nitrous oxide as a simple and non-invasive alternative to other pain relief options.

Using Gas During Labour

Here’s what you need to know about gas and using it during childbirth labour:

How Does Gas Work?

Nitrous oxide (NO) is breathed in via a mask or mouthpiece. The gas enters the lungs, and then is absorbed quickly into the bloodstream. It passes around the body, reaching the brain within 15 seconds.

The amount of nitrous oxide that reaches the brain depends on the percentage being used. It’s not understood exactly how nitrous oxide provides pain relief, but it is thought to alter how we perceive pain.

How Do You Use Gas?

The best way to use nitrous oxide is to begin breathing from the mask or mouthpiece at the beginning of each contraction. You keep breathing deeply and evenly until you feel light headed, then take the mouthpiece or mask away. After a few seconds the light headed feeling will pass.

It takes time for the effect of nitrous oxide to build up in your system, and you may not feel the full effects until you have been breathing the gas for around 60 seconds.

It may take you a few tries to get the hang of the timing, but it’s important to start breathing the gas as soon as your contraction starts, not during, so that you get the greatest amount of relief at the peak of your contraction.

Are There Any Side Effects Of Using Gas?

A study in 1990 found that women who were given 100% nitrous oxide during labour gave birth to babies who were 5.5 times more likely to have an amphetamine addiction, than siblings who were not exposed to nitrous oxide during labour.

High doses of nitrous oxide can interfere with your body’s vitamin B12 levels as well as cell development. While it is unlikely you would be using high percentages of nitrous oxide during labour (it’s common to start with 50/50 but this can be adjusted from 0-100), women with B12 deficiency should not use nitrous oxide.

There is also some concern for midwives being exposed to large amounts of nitrous oxide due to the potential reproduction risks. Equipment should have a demand valve and scavenging equipment to limit exposure.

What Are The Pros of Gas During Labour?

  • Nitrous oxide is not broken down by the liver, so it’s quickly eliminated by your body via your lungs
  • Your baby also is able to quickly eliminate nitrous oxide
  • Using gas means you are able to stay awake and conscious during your labour and the baby’s birth
  • Women administer their own gas, so they’re in control of their own pain relief
  • It does not disrupt oxytocin, so it will not interfere with post birth bonding
  • It can provide relief from anxiety
  • Nitrous oxide does not slow or increase contractions, so there is no impact on the tempo and progress of your labour
  • It’s only used during a contraction, so it may take the edge off the pain, but it does not effect you immediately after the contraction has ended
  • Can help during transition to give you something to focus on while breathing (you could even try all oxygen)
  • Your baby won’t need extra monitoring while you are using gas
  • May help you avoid using an epidural or narcotic medication that have more adverse effects on you and your baby

What Are the Cons of Gas During Labour?

  • The pain relief can vary for women — some don’t find it provides enough relief
  • It can make you feel nauseous and cause you to vomit
  • Nitrous oxide can take a while to get the timing right for full effect
  • Gas can make you feel drowsy and confused, even disorientated
  • Nitrous oxide depresses normal brain function
  • Your mouth can become very dry if you use nitrous oxide for long periods
  • You can feel unsteady while using gas and may end up confined on the bed
  • If you breathe too much nitrous oxide you can lose consciousness
  • Gas does cross the placental barrier, with unknown long term effects on the baby
  • You may be limited in mobility as the mouthpiece or mask may be attached to a wall unit
  • Women should be screened for B12 levels before use


Jacobson, B. et al. (1990) Opiate addiction in adult offspring through possible imprinting after obstetric treatment. British Medical Journal, 301: 1067-1070.

Recommended Reading

For more information about pain relief during labour, see BellyBelly’s article, Natural Pain Relief Options For Labour – 13 Effective Options.

Last Updated: June 30, 2015


Sam McCulloch enjoys talking so much about birth that she decided to become a birth educator and doula, supporting parents in making informed choices about their birth experience. In her spare time she watches Downton Abbey and has numerous creative projects on the go. She is mother to three beautiful little humans.

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