This is a mixture of oxygen and another gas called nitrous oxide, which is now considered to be one of the safest and most versatile methods of pain relief in labour. It is also used in several other specialist procedures, e.g. in medical, surgical, dental, casualty units and so on.
Pain relief is obtained through inhalation from a small apparatus made up of a lightweight face mask, a valve and tubing connected to a particular supply. The mask fits snugly to the face while the valve is dual purpose, permitting freedom to breathe in and out without removing the face mask.
A demonstration is usually given in antenatal classes.
In labour the Entonox is given at the midwives discretion. Direct supervision is not necessary and once advised by the midwife the mother can help herself. To ensure that the maximum effect is achieved it’s best to start inhaling the Entonox at the very first sign of the contraction. Breathe very deeply in and out – keeping the mask firmly in place until the contraction subsides. Then, breathe normally while awaiting the next pain.