Oral contraceptive use and myocardial infarction.

Epidemiologic studies of current oral contraceptive (OC) use and myocardial infarction (MI) have been contradictory and confusing. This comprehensive review of the epidemiologic literature attempts to draw conclusions about the risk of myocardial infarction in oral contraceptive users, focusing on recent, methodologically rigorous studies of the topic. Recent studies are consistent in showing a higher relative risk of MI in current OC users who smoke compared with current OC users who do not smoke. Studies in aggregate suggest that the relative risk of MI is higher in current OC users with hypertension than in current OC users without hypertension. Recent studies do not show a relationship between higher estrogen dose and higher risk of MI, but the effect of estrogen dose and progestogen type and dose are difficult to separate. The limited data on the risk of MI in current users of low estrogen OC do not allow a firm conclusion about the possibility that progestogen type might affect the risk of MI in current users. Past OC use does not increase or decrease the risk of MI.