Estradiol containing oral contraceptive

Combined oral contraceptives that contain natural estradiol or an estradiol ester (e.g., estradiol valerate) include:

It is hypothesized that these contraceptives may pose less of a risk of blood clots than contraceptives containing ethinylestradiol, which is the conventional estrogen that is used in oral contraceptives, but this has yet to be proven. However, incidence of irregular vaginal bleeding may be higher with estradiol-containing contraceptives in relation to the fact that estradiol is a weaker estrogen than ethinylestradiol in the endometrium.

Estradiol, mainly as esters including estradiol valerate, estradiol cypionate, and estradiol enanthate, is the exclusive estrogen used in combined injectable contraceptives.