How much bleeding is 'excessive'?

In normal births, the mother usually loses a small amount of blood (about 150 ml or a cupful) as the baby is born and after delivery of the placenta. When the amount exceeds 300 ml (2 cupfuls) it is considered as heavy bleeding (Figure below).

Excessive bleeding is often defined as more than 500 ml of blood loss. However, for severely anaemic women, blood loss of even 200–250 ml can be fatal.

For that reason, a better definition of postpartum haemorrhage might be 'any amount of bleeding that causes deterioration in the woman's condition and signs of haemorrhagic shock', i.e. low blood pressure, fast pulse, pallor, weakness or confusion).