Cardiovascular issues with oral contraceptives: evidenced-based medicine

Recent studies of current oral contraceptives indicate that the risk of cardiovascular sequelae is low in young (age 20-24 years) reproductive-aged women. Venous thromboembolism remains the one event that occurs in users independent of the presence of risk factors. However, the attributable risk is small, in the range of 7 to 18 events per 100,000 women annually. This risk is proportional to estrogen dose until the level of 30-35 microg is reached; type of progestin may also influence risk, though recent studies are controversial. Modifiable risk factors for venous thromboembolism include the presence of hemostatic disorders, especially factor V Leiden, and perhaps obesity. Stroke is even more uncommon, with an attributable risk of about 1.5 events per 100,000 women annually. Cigarette smoking and hypertension are modifiable risk factors for both ischemic and hemorrhagic stroke; use of preparations with 50 microg of estrogen or higher and migraine headaches are risk factors for ischemic stroke. Eliminating risk factors among users substantially reduces the risk of ischemic stroke and virtually eliminates the risk of hemorrhagic stroke. Myocardial infarction is rare among young women, occurring at a rate of about 0.2 event per 100,000 women annually. Oral contraceptive users who are non-smoking and normotensive do not have an increased risk of myocardial infarction. However, the presence of these risk factors along with age acts synergistically to increase the risk among oral contraceptive users.