Means for relieving pain should be made available to every mother in labour. No mother should hesitate to ask for relief and it should be given to her when required, although always within the limits of safety to her and her baby. Many who achieve a truly natural birth will not need such reliefs.
The aim of pain relief in childbirth is always to give the maximum relief to the mother with the minimum of harmful effect on her and on the baby. This is by no means an easy problem, since everything given to the mother tends, to pass over to the baby to a varying extent. Numerous agents have been used to relieve pain in childbirth and new drugs and methods are continually being discovered and invented. It will, therefore, be possible to mention only a few and consideration will be confined to those at present in general use.
The agents used can be divided into three main groups; these groups overlap each other to some extent, but it is important to define the nature and uses of each group. The first group is sedatives.

The first stage of labour lasts twelve to twenty-four hours with a first baby and usually less with subsequent children. During these hours the contractions of the uterus increase in strength and come more frequently until by the end of the first stage they may be occurring every three to five minutes. The cervix or neck of the womb undergoes several important changes. First it is drawn up so that it no longer projects into the vagina; then it gradually opens or dilates. By the end of the first stage the opening in the cervix is large enough to allow the baby’s head to pass into the vagina. The cervix itself is now almost non-existent and the uterus and vagina have been converted into one continuous cavity. In the majority of labours the membranes rupture and the waters escape towards the end of the first stage, though they may rupture much earlier, and in a few cases they do not rupture before the birth of the baby. The baby may then be born completely enclosed in the membranes or “caul,” an event which was once thought to be an omen of great good fortune.