Delivery

The expulsion or extraction of a baby from the mother’s uterus. In most cases, the baby lies lengthwise in the uterus with its head facing downwards and is delivered head first through the vaginal opening by a combination of uterine contractions and maternal effort (see childbirth). If the baby is lying in an abnormal position (see breech delivery; malpresentation), if uterine contractions are weak, or if the baby’s head is large in relation to the size of the mother’s pelvis, a forceps delivery or vacuum extraction may be required. If a vaginal delivery is impossible or dangerous to the mother or the baby, a caesarean section is necessary.