the prognosis of pulmonary arterial hypertension (who group i) has an "untreated" median survival of 2–3 years from time of diagnosis, with the cause of death usually being right ventricular failure (cor pulmonale). a recent outcome study of those patients who had started treatment with bosentan (tracleer) showed that 89% patients were alive at 2 years. with new therapies, survival rates are increasing. for 2,635 patients enrolled in the registry to evaluate early and long-term pulmonary arterial hypertension disease management (reveal registry) from march 2006 to december 2009, 1-, 3-, 5-, and 7-year survival rates were 85%, 68%, 57%, and 49%, respectively. for patients with idiopathic/familial pah, survival rates were 91%, 74%, 65%, and 59%. levels of mortality are very high in pregnant women with severe pulmonary arterial hypertension (who group i). pregnancy is sometimes described as contraindicated in these women.