Six young women who had taken progestational agents for a period of time ranging from six months to five years developed symptoms and signs of pulmonary hypertension. Cardiac catheterization confirmed the presence of severe pulmonary hypertension without evidence of other cardiac or pulmonary abnormalities to explain this phenomenon. Three of the patients had potential predispositions to pulmonary hypertension, including a corrected patent ductus arteriosus with mild pulmonary hypertension in one, collagen vascular disease in a second, and family history of pulmonary hypertension in a third. Three patients had no known predisposing factors. Although the relationship between oral contraceptives and severe pulmonary hypertension is problematic, there have been isolated reports of cases of pulmonary hypertension secondary to oral contraceptive usage. These cases and the possible pathophysiologic mechanisms responsible are discussed.