Reproductive health/Progesterone

Progesterone is a hormone that is normally found in women and it reaches particularly high levels during pregnancy. Progestins are synthetic drugs that mimic the biological actions of progesterone and they have been widely prescribed to women. This learning project allows Wikiversity participants to explore health-related topics that involve progesterone and synthetic drugs that act on progesterone receptors.

Progesterone, progestins and breast cancer
The Wikipedia articles on breast cancer and progestins do not mention that breast cancer rates appear to be increased by progestin use. Wikipedia articles for the Women's Health Initiative and Hormone replacement therapy do mention some of the clinical trial results that link progestin use to increased breast cancer risk. Recent studies suggest mechanisms by which progesterone receptors might stimulate breast tumor growth. The Wikipedia article on Bioidentical hormone replacement therapy raises the question: might progesterone use pose less breast cancer risk than use of synthetic progestins?

Why are progestins so widely prescribed?
Progestins are widely used by both younger women and older women. Younger women of reproductive age often use progestins for hormonal contraception. Older women have frequently been prescribed combinations of estogen and progestins as Hormone replacement therapy when endogenous levels of estrogen decline. Combined estrogen and progestin administration is used to limit the incidence of estrogen supplement-induced endometrial cancer.

News reports
This is a running list of news reports related to progestrone, progestins and related health issues such as breast cancer.

Lawsuits
October 30, 2007. "Wyeth is facing more than 5,000 lawsuits from those who believe they were harmed by the hormone replacement drugs, which have been used by millions of women to control the effects of menopause." Wyeth is the manufacturer of Premarin and Prempro, a mixture of medroxyprogesterone and Premarin.

The Women's Health Initiative estrogen-plus-progestin study reported an increased rate of breast cancer for women using Prempro. The Food and Drug Administration now requires that the Women's Health Initiative results for breast cancer be provided to patients who use Prempro (Label).

Brest cancer incidence
December 15, 2006. Following the release of results from the WHI Prempro clinical trial (see above), "Within six months, the drug's sales had fallen by 50 percent." Breast cancer incidence also declined during this time: "The reason, researchers believe, may be that millions of women during that time abandoned hormone treatment for the symptoms of menopause"

Epidemiological studies report that since women started to become aware of the risks associated with progestin use, decreases in incidence of breast cancer parallels the decline in progestin use, consistent with the known increased risk of breast cancer among women who use progestins.

Using progesterone rather than progestins
January 16, 2007. The North American Menopause Society (NAMS) is a nonprofit organization concerned with menopause. T.V. correspondent Dr. Emily Senay reported that the NAMS has urged doctors not to prescribe natural hormones like progesterone for menopausal women Large clinical trials have not been performed to test the efficacy and safety of natural hormones like progesterone for treating the symptoms of menopause.

Who would pay for clinical research studies on progesterone? One possibility is that government funding would be provided in an attempt to find alternatives to synthetic progestins, but is there a level playing field for discussion of such studies when drug companies make large profits from synthetic progestins? The International Academy of Compounding Pharmacists has suggested that The North American Menopause Society is not an independent voice because it is supported by progestin manufacturers.North American Menopause Society’s Ties to Wyeth Pharmaceuticals

One recent reviewer concluded that there needs to be more research on bioidentical hormones and that there is, "evidence to support their preferred use over that of their synthetic cousins." Other reviewers have reached the opposite conclision.

A major concern for use of progesterone rather than synthetic progestins is that progesterone is rapidly metabolized in the body. There are many different formulations of mixtures of estrogen and progesterone and various methods for administering them. There has been concern about quality control for progesterone both in terms of variability in amounts and efficiency of absorption. Some women have used bioidentical hormone treatments for extended periods of time without monitoring for possible stimulation of uterine tissue growth. Women should not assume that bioidentical hormone treatments are safe just because they use natural hormones. Supplements containing natural estrogen can cause endometrial cancer.

Related resources

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