Systemic hormonal contraception and risk of venous thromboembolism.

An increased risk of venous thromboembolism is associated with ethinylestradiol-containing combined preparations. The use of estradiol-containing combined preparations confers only a slightly increased risk, possibly driven by cyproterone-containing combined oral contraceptives, whereas the use of progestin-only contraception is not associated with venous thromboembolism.