Gas and air, also known as “laughing gas” or Entonox, is often used by women for pain relief during labour. Although it won’t get rid of labour pains completely, it will certainly reduce the pain and about 80% of women use it, making it by far the most common method of relieving pain in labour.
Gas and air is a mixture of oxygen and nitrous oxide gas, which can be supplied in cylinders (in the case of a home birth, for example) or pumped from a central supply, as is more often the case in a hospital setting.
How to use gas and air
You are in control of the gas and air and can use it throughout your labour. You’ll be given your own mouthpiece or a mask, which is used to deliver the gas, and your midwife will show you how to use it. You may also have the opportunity to try it an antenatal class.
As you breathe in the gas and air you may feel a little lightheaded and giggly – it takes about 20 seconds of slow, deep breathing to get enough gas and air into your system, and it can take a few minutes to feel the full pain relieving impact. It’s best to start taking the Entonox as soon as a contraction is beginning so that you get the maximum pain relief when the contraction is at its strongest. Between contractions it’s best to have a break from the gas and air – if you take it constantly for long periods it can make you feel more lightheaded or dizzy.
What are the advantages of gas and air?
It's easy to use
It reduces the pain (although it doesn’t take the pain away fully)
It doesn't stay in your system; as soon as you stop breathing it in, your lungs clear out all the gas and air in your system and if you have any side effects then they will stop too
It's under your control
It's flexible and quick-acting
It's perfectly safe for your baby
You and your baby won’t need extra monitoring while you're using it
You can use it in the water if you want to labour in a birth pool or in the bath
What about the disadvantages?
It is only a mild painkiller
It can make some people feel drowsy, light-headed or sick
It may dry out your mouth if you use it for too long
Keeping hold of the mouthpiece or mask may prevent you from moving around and getting into a comfy position
It sometimes takes a little while to get the timing right so that it's effective when your contractions peak
It may make you feel even more drowsy if you use gas and air with a stronger pain relief drug like pethidine or morphine
Dr Emma Scott (MBChB, MRCGP) is a qualified GP and mummy to two young children. She works in a GP practice in Edinburgh and in the out of hours GP service in Livingston and she has experience in both obstetrics & gynaecology and paediatrics.