Segesterone acetate (elcometrine), a progestin, is sold in combination with ethinyl estradiol under the brand name Annovera. Annovera is indicated for use by females of reproductive potential to prevent pregnancy. Segesterone acetate acts as an agonist of the progesterone receptor and it doesn’t possess estrogenic, androgenic, antiandrogenic, or antimineralocorticoid activity.

Ulipristal acetate (also known as CDB-2914 and PGL4001 and trade name Ella in the U.S) is a novel oral emergency contraceptive designed and developed by HRA Pharma. It is a selective progesterone receptor modulator, which reversibly blocks the progesterone receptors in target tissues it was approved in May 2009 by the European Commission and in August 2010 by the FDA as safe and effective in preventing unintended pregnancy for up to 120 hours – or five days – post- unprotected intercourse or contraceptive failure. Ella is not intended for routine use as a contraceptive. When taken immediately before ovulation is to occur, ella postpones follicular rupture. The likely primary mechanism of action of ulipristal acetate for emergency contraception is therefore inhibition or delay of ovulation; however, alterations to the endometrium that may affect implantation may also contribute to efficacy. The most common side effects are: headache, nausea, stomach (abdominal) pain, menstrual pain. Some women taking ella may have their next period earlier or later than expected. If your period is more than a week late, you should get a pregnancy test.

Chlormadinone acetate (CMA) is a derivative of naturally secreted progesterone that shows high affinity and activity at the progesterone receptor. It has an anti-estrogenic effect and, in contrast to natural progesterone, shows moderate anti-androgenic properties. CMA acts by blocking androgen receptors in target organs and by reducing the activity of skin 5alpha-reductase. It suppresses gonadotropin secretion and thereby reduces ovarian and adrenal androgen production. CMA shows high contraceptive efficacy by inhibiting ovulation due to its ability to suppress or disrupt endogenous gonadotropin secretion and, by this, inhibits follicular growth and maturation. In addition, it suppresses endometrial thickness and increases the viscosity of cervical mucus. Chlormadinone acetate was withdrawn from the market in the USA, but it is still being used in Europe under the name Belara.