Estradiol stearate
Estradiol stearate (brand name Depofollan), or estradiol octadecanoate, is a naturally occurring steroidal estrogen and an estrogen ester – specifically, the C17β stearate ester of estradiol. It occurs in the body as a very long-lasting metabolite and prohormone of estradiol. In addition, estradiol stearate is or has been available as a pharmaceutical drug for use via depot intramuscular injection. The drug was introduced in 1941 as Depofollan and was the first long-acting estrogen, although it has never been widely used. It has been reported in at least one source to have a duration of at least one month.
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.