Pulmonary hypertension may be either primary of unknown aetiology or secondary to existing cardio-respiratory disease. As a single entity the prognosis is poor but superimposition of the physiological changes of pregnancy and labour produces a lethal condition. This paper sets out two clinical cases of primary pulmonary hypertension as background for discussion to highlight the issues involved. Whatever this discussion does, let it be clearly spelled out that prevention is better than any proposed cure.