This is a complication in which the placenta is placed by itself in front of the head of the baby and covers the orifice in the neck of the uterus. This situation is frequent until week 20 of pregnancy. Nevertheless, if towards the date of the childbirth, the placenta continues to be located in this place, the vaginal childbirth becomes impossible and a caesarean section will be necessary. There can be some bleeding, which sometimes is normal. But if haemorrhage is abundant, this must be immediately treated.