Hormone in Birth Control May Lower Risk of Ovarian Cancer

A study published in yesterday’s Journal of the National Cancer Institute identifies the hormone progestin as one of the potential causes for the lower risk of ovarian cancer in women who use oral contraceptives. The study reviewed and compared data on almost 3,000 women, including contraceptive users and non-users, between 20 and 54 years old. As expected, women who used oral contraceptives were less likely to develop ovarian cancer than women who did not use this form of birth control. Interestingly, however, women using low-potency progestin oral contraceptives were two times as likely to develop the disease than women using high-potency progestin pills. Researchers believe that progestin, an synthetic progesterone, increases the rate of cell death in the lining of the ovaries, including the death of abnormal cells, thereby decreasing a woman’s risk of developing ovarian cancer. The type of contraceptives used in the studies however, are generally not the formulations most commonly used today (women generally have fewer side effects with birth control pills containing lower doses of estrogen and progestin).

Controversy exists regarding dosages of hormones and their ability to diminish risk for ovarian cancer. A study by Ness et al. indicated that the risk-reduction for ovarian cancer associated with the use of low-estrogen/low-progestin pills was identical to that associated with the use of high-estrogen/high-progesterone pills. Other progestin only contraceptives such as Depo-Provera, which has an even higher dose of progestin than the high-progestin birth control pills, interestingly does not confer a lower risk for developing ovarian cancer. Researchers from the Journal of the National Cancer Institute also warn that pills higher in progestin may be associated with a greater risk of some types of breast cancer. The researchers emphasized that the take-home message of the study is that oral contraceptives are protective against ovarian cancer and the finding of higher progesterone conferring increased protection may be useful in leading to new drugs which could prevent ovarian cancer.

The Feminist Majority Foundation has long called for continued research into the multiple medical uses of mifepristone (RU-486), the first synthesized anti-progesterone drug. Anti-abortion politics has made it difficult for scientists to obtain this drug to study the role of progesterone in the development of ovarian cancer, breast cancer, endometriosis and fibroids, among other diseases primarily afflicting women.


Reuters Health, 1/2/02; Schildkraut et al., Journal of the National Cancer Institute, Vol. 94, No. 1, 32-38, January 2, 2002; Ness et al., American Journal of Epidemiology 2000, 152:233-41; Kaisernetwork.org 1/2/02

Support eh ERA banner