Cerebral vein thrombosis and the contraceptive pill in paroxysmal nocturnal haemoglobinuria.

A young woman who developed a cerebral venous thrombosis shortly after commencement of an oral contraceptive preparation was subsequently found to have paroxysmal nocturnal haemoglobinuria. The aetiology of thrombotic complications in this condition is discussed, with particular reference to the additional risk factor of the contraceptive pill in this case.