In most cases, myocardial infarction is caused by blockages in coronary arteries by thrombosis. Myocardial infarction is uncommon in women of reproductive age. Because of this, studies of large populations are needed to determine factors that cause this condition in this population group. Only limited data are available, which show that age, cigarette smoking, diabetes, hypertension and raised total blood cholesterol are important risk factors for myocardial infarction in young women.
Most contraceptive users are healthy with a low incidence of major disease.
Thus, even though serious adverse events occur infrequently in contraceptive users, they tend to have greater implications than adverse events arising during the treatment of sick patients. In addition, the very large number of women using steroid hormone contraceptives throughout the world means that even a modest rise in risk has the potential to affect a large number of women. The first report of coronary thrombosis in an oral contraceptive user was published in 1963. The results of the first epidemiological studies of vascular disease in oral contraceptive users were published in the late 1960s but only two presented data on myocardial infarction and neither found an elevated risk in current users of oral contraceptives. Subsequent studies, however, suggested such risk may be present.