Entonox is a mixture of oxygen and a gas called nitrous oxide. You breathe it in through a mask or mouthpiece that you hold yourself. Gas and air won’t remove all the pain, but it can help by reducing it and making it easier to bear. Many women like it because it’s easy to use and you control it yourself. Some women report using gas and air gives them something to concentrate on, the gas takes about 15–20 seconds to work, so you breathe it in just as a contraction begins. There are no harmful side-effects for you or your baby, but it can make you feel slightly light-headed. Some women also find that it makes them feel sick or sleepy or unable to concentrate. If this happens, you can simply stop using it as the effects wear off quickly.
If you try gas and air and find that it does not give you enough pain relief, you can ask for an alternative method.
For more information visit www.nhs.uk/conditions/pregnancy-and-baby/pages/pain-relief-labour