We reviewed evidence that bears on the cardiovascular safety of combined oral contraceptives containing second- and third-generation progestogens and < 50 micrograms of estrogen. Recent epidemiologic studies indicate that current use of these formulations is associated with a smaller increase in the incidence of venous thromboembolism than earlier formulations. In some studies the increase for third-generation formulations containing desogestrel or gestodene was about 1.5 to 2 times that for second-generation formulations, but there is evidence that differences between users in underlying risk and likelihood of being diagnosed contributed to this result. Recent studies of myocardial infarction suggest a smaller increase in risk associated with modern formulations than with earlier ones; one study suggests a threefold increase for second-generation formulations and no increase for third-generation formulations, but the finding requires confirmation. Recent studies of stroke indicate little or no increase in risk for modern formulations among women without risk factors. We conclude that modern combined oral contraceptives are safer than earlier formulations with respect to cardiovascular disease, which occurs rarely in young women.
PIP: This review of the research literature on the cardiovascular safety of oral contraceptives (OCs) containing less than 50 mcg of estrogen and second- or third-generation progestins suggests that these formulations are safer than earlier OCs were. Although some recent studies detected an increased risk of venous thromboembolism of 1.5-2.0 in users of OCs containing desogestrel or gestodene compared with second-generation progestins, these studies are marred by detection bias and the tendency for high-risk women to be prescribed third- rather than second-generation OCs. Studies of the association between combined OCs and myocardial infarction have yielded discrepant results; one found an increased risk with second- but not third-generation OCs. Studies on stroke indicate little or no increase in risk in users of modern OCs without other cardiovascular risk factors. Overall, the available research indicates that use of second- or third-generation OCs carries less risk of venous thromboembolism than pregnancy. In addition to the prevention of pregnancy and its attendant risks, low-dose OCs confer additional health benefits such as reductions in the incidence of ovarian and endometrial cancer.