Is "estrogen dominance" theory bunk?

Q: My family physician suggested I research progesterone supplementation and “estrogen dominance” theory. Is there any independent research to support or debunk this theory?

A: Progesterone/estrogen balance is a controversial topic in gynecology. Certainly, as we get older (into our late 30s and 40s), we ovulate less well. We therefore produce less progesterone, partly explaining why we are less fertile at this time of our lives. Also, women who are heavy make more estrogen than their slimmer sisters. (Remember, fat tissue is not inert. Fat actually takes a hormone made by our adrenal glands, called androstenedione, and converts it into estrogen. And this estrogen is not balanced by progesterone.)

The question, then, is what this excess estrogen does. In particularly heavy women, for example, it increases their chances of developing cancer of the lining of the uterus, and many physicians will treat heavy women – particularly those with abnormal bleeding – with progesterone as a preventive measure.

In other women, the question of estrogen excess has been suggested as one cause of PMS. Dr. Katharina Dalton is a famous British physician who has advocated taking progesterone premenstually for PMS sufferers. However, many studies in the U.S. have failed to show the response to progesterone supplementation that she has shown. I certainly have tried progesterone for some women with PMS, particularly if they have menstrual bleeding difficulties as well, and have had some success with it. Some experts would also recommend in those situations to try a low-dose birth control pill, as these pills are progesterone dominant, and shut down the excess estrogen production.

To summarize, I think taking progesterone is quite safe. The only question is, how much good will it do?

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