Inhalation of 50% nitrous oxide with 50% oxygen, can give very effective pain relief during labor and is safe for the mother and baby.

It is safest when self-administered by the mother, under the guidance of her birth attendant. If she feels dizzy or starts to achieve anesthetic levels of the nitrous, she will naturally release the mask, quickly reversing the effects of the nitrous oxide.

Less commonly used is a self-administered volatilized gas of methoxyflurane. It is capable of achieving anesthetic levels and so must be very closely monitored, particularly when first initiated.