Epidurals work by blocking pain nerves as they enter the spinal cord. A local anaesthetic is injected to numb the area of the lower back before the procedure is carried out. A special needle is then carefully inserted in to the space near to where the nerves enter the spinal cord. A fine tube is then pushed carefully through the needle and left in place so that drugs can be run through it. A side effect is that your legs may feel numb and unable to hold your weight. This can restrict your movements and feelings of when to push. As a result, it may slow the labour or increase the risk of a forceps or ventouse delivery slightly.
The availability of epidurals will depend on each hospital. It is best to ask your midwife what happens at the hospital you are booked at.
See: Goer, H. (1995) Obstetrical myths and research realities: a guide to the medical literature. Bergin and Garvey, London.