Estrogen (medication)
Estradiol, estrone, and estriol have all been approved as pharmaceutical drugs and are used medically. Estetrol is currently under development for medical indications, but has not yet been approved in any country. A variety of synthetic estrogen esters, such as estradiol valerate, estradiol cypionate, estradiol acetate, estradiol benzoate, estradiol undecylate, and polyestradiol phosphate, are used clinically. The aforementioned compounds behave as prodrugs to estradiol, and are much longer-lasting in comparison when administered by intramuscular or subcutaneous injection. Esters of estrone and estriol also exist and are or have been used in clinical medicine, for example estrone sulfate (e.g., as estropipate), estriol succinate, and estriol glucuronide (as Emmenin and Progynon).
Estetrol (medication)
In addition to a single-drug formulation, estetrol is under development in combination with the progestin drospirenone for use as a birth control pill to prevent pregnancy with the tentative brand name Estelle. Drospirenone is also a potent antimineralocorticoid and antiandrogen in addition to progestogen, and in relation to this, is said to have a progesterone-like medication profile. As of April 2018, estetrol/drospirenone are in phase III clinical trials for pregnancy prevention.