How Do Progestins Work?

Reviewed on 12/29/2021

How do progestins work?

Progestins are hormonal medications used for contraception and in the treatment of many menstrual disorders such as abnormal uterine bleeding, lack of menstruation (amenorrhea), and endometriosis. Progestins are also used as palliative treatment in advanced stages of certain cancers including endometrial, renal, and breast cancers.

Progestins are synthetic formulations of the natural female sex hormone progesterone and have similar effects. Progesterone regulates the reproductive cycle in women, along with another hormone estrogen. Progesterone plays a vital role in the regulation of menstruation, implantation, maintenance of pregnancy, and fetal growth.

The reproductive cycle is regulated by a system known as the hypothalamic-pituitary-gonadal axis. The hypothalamus secretes gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

The hormones FSH and LH stimulate ovulation and the production of estrogen. After ovulation, the remains of the follicle (corpus luteum) produce progesterone, in addition to estrogen. After pregnancy, the placenta also starts to produce progesterone, keeping its levels high and preventing ovulation during pregnancy.

Estrogen stimulates the growth of the endometrium, the inner lining of the uterus, while progesterone prepares it for implantation and pregnancy. Progesterone also stimulates the growth of breast tissue, readying it for lactation. In the absence of conception, the hormone levels fall, leading to menstruation and the beginning of a new cycle.

Progestins work by binding to progesterone receptors, which are protein molecules in cells that respond to progesterone. Progestins work in many ways to prevent pregnancy, regularize menstruation and prevent endometrial tissue growth.

  • Progestins prevent pregnancy in the following ways:
    • Inhibiting ovulation by reducing the release of GnRH from the hypothalamus and release of FSH and LH from the pituitary gland
    • Thickening the cervical mucus, hindering the passage of sperm into the uterus
    • Preventing implantation by thinning the endometrium
  • Progestins regularize menstruation by restoring hormonal balance and also supplement natural progesterone deficiency in assisted reproductive therapies
  • Progestins have antiestrogenic properties, thought to help in reducing endometrial tissue growth and pain associated with endometriosis, and slowing down the progress of certain types of estrogen-dependent cancers


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How are progestins used?

Progestins may be administered through many routes including the following:

The uses of progestins include:


  • Contraception in females with reproductive potential.
  • Treatment of heavy menstrual bleeding.
  • Emergency post-intercourse contraception following unprotected vaginal intercourse, or known or suspected contraceptive failure.
  • Metastatic endometrial carcinoma (as adjunctive therapy and palliative treatment).
  • Metastatic renal carcinoma (as adjunctive therapy and palliative treatment).
  • Breast cancer (palliative treatment in advanced disease).
  • Cancer-related cachexia (weakness due to wasting of the muscle and weight loss).
  • Acquired immunodeficiency syndrome (AIDS)-related cachexia.
  • Secondary amenorrhea (absence of menstruation) is due to hormonal imbalance, and not because of pathologic reasons such as uterine fibroids or cancer.
  • Abnormal uterine bleeding due to hormonal imbalance, and not because of pathologic reasons such as uterine fibroids or cancer.
  • Prevention of endometrial hyperplasia (thickening) in postmenopausal women on estrogen for hormone replacement therapy (HRT) for menopausal symptoms.
  • Management of pain associated with endometriosis (a disorder in which endometrial tissue is present outside the uterus).
  • As part of assistive reproductive technology (ART) treatment for infertility in women with progesterone deficiency.
  • Reduction of risk of preterm labor in women who have a history of spontaneous preterm birth. The FDA has proposed withdrawal of this approval because the available evidence does not show the effectiveness of progestins for this use.

Orphan designation:

What are the side effects of progestins?

Side effects of progestins may include the following:

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with travel medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.


If menopause occurs in a woman younger than ___ years, it is considered to be premature. See Answer

What are the names of progestin drugs?

Generic and brand names of progestin drugs include:


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