Two cases of successfully managed Eisenmenger's syndrome during pregnancy are reported. A women suffering from Eisenmenger's syndrome who becomes pregnant should be advised to have her pregnancy terminated. On the basis of the available literature and our own experiences we suggest the following plan, if a woman, despite medical advice, chooses to continue her pregnancy: admission to hospital at approximately 25 weeks of gestation; bed rest during the remaining period of pregnancy; oxygen face-mask during episodes of dyspnoea; determination of serial blood gases to detect changes in the shunt flow. At the onset of labour, arterial and epidural catheters should be inserted, a fall in blood pressure should immediately be counteracted by the administration of norepinephrine and loss of blood by transfusion. The patient should remain in hospital for 7-14 days after delivery.