The clinical features of placental abruption depend on the size and site of the bleeding. A bleed which tracks down behind the membranes and appears through the cervix is said to be 'revealed'; that which occurs retroplacentally, is said to be 'concealed'.
The grades of haemorrhage described are:
- mild - in this case there is only a small area of placental separation and the blood loss is usually less than 200ml. There may be abdominal discomfort and the uterus may be tender
- moderate - up to a 1/3 of the placenta separates. There is more severe bleeding (200-600 ml). The patient complains of abdominal pain. On examination the patient may have tachycardia but does not have signs of hypovolaemia. The uterus is tender. Fetal heart sounds are present
- severe - in this condition more than half of the placenta separates. The abdominal pain is more severe. On examination the uterus is tender and rigid - it may be impossible to feel the fetus. Fetal heart sounds are reduced or absent. The patient may be in a state of hypovolaemic shock