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, 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.