Coagulation disorders.

The risk of severe haemorrhage in pregnancy is well recognized, and uncontrolled bleeding remains a major cause of maternal death throughout the world, including the British Isles. The haemochorial system of human placentation carries with it an inherent risk of haemorrhage and this probably explains why the serious congenital disorders of haemostasis are predominantly found in the male. In pregnancy, complex physiological changes occur in the systems responsible for the control of blood loss from the vascular tree.