Hormone therapy with high-dose ethinylestradiol and cyproterone acetate in transgender women has been associated with a 20- to 45-fold higher risk of VTE relative to non-use. The absolute incidence was about 6%. Conversely, the risk of VTE in transgender women is much lower with oral or transdermal estradiol plus high-dose cyproterone acetate. Ethinylestradiol is thought to have been primarily responsible for the VTE risk, but cyproterone acetate may have contributed as well. Ethinylestradiol is no longer used in transgender hormone therapy, and doses of cyproterone acetate have been reduced.