Cardiovascular risks: perception versus reality.

The high estrogen doses in the original oral contraceptive (OC) formulations were associated with an increased risk of cardiovascular events. Since then the steroid doses in OC have been reduced steadily, so that current low-estrogen-dose (< or = 35 micrograms) combination OC are associated with a lower risk of arterial and venous events than occurs with higher-estrogen-dose formulations. Based on the currently available epidemiologic evidence, the following conclusions can be made regarding the cardiovascular disease risks associated with use of low-dose OC by healthy, nonsmoking women: there is no increased risk of myocardial infarction (MI) or hemorrhagic or ischemic stroke; and there is a three- to fourfold increased risk of venous thrombosis and embolism (VTE). This risk is about half that associated with pregnancy. Smoking is the most important independent risk factor for MI, and is synergistic with OC use. Women smokers should be advised strongly to stop smoking, but those aged < 35 years may use any OC containing < or = 35 micrograms of estrogen. Women smokers aged > or = 35 years should be advised to use a nonestrogen or nonhormonal contraceptive method.