Risk of Cardiovascular Events with Hormonal Contraception: Insights from the Danish Cohort Study

Hormonal contraception in the form of combined oral contraceptive pills is the most widely used reversible form of contraception in the US. Oral contraceptive (OC) pills have long been associated with risk of venous thromboembolism (VT) and arterial thrombosis (AT). There are more recent publications on risk of venous thromboembolism than arterial thrombosis. Many of the studies on AT have been contradictory in terms of results. The Danish cohort study is the largest study to date on the risk of AT in users of oral contraceptive pills. The study suggests that a lower estrogen dose may be better for preventing myocardial infarction and possibly thrombotic stroke but there is no significant difference according to progestin type for risk of thrombotic stroke or myocardial infarction. It challenges results of previous studies that show incremental risk of arterial thrombosis with smoking. The absolute and relative risks of arterial thrombosis in Danish women who used hormonal contraception were shown to be low. VT is more common than AT in women of reproductive age but AT is associated with a higher risk of mortality and disability. The decision to use hormonal contraceptives and the choice of formulation should be individualized based on patient's age and known risk factors for both VT and AT.