For most women, the estrogen levels will begin falling as she goes through her thirties. With the approach of menopause, some women will begin experiencing dry skin, brittle hair, and a loss of libido. Finally, as menopause itself arrives, many women will experience hot flashes, depression, loss of energy and even crying spells. For many women, estrogen replacement has shown that it can manage and reduce these symptoms. Some studies have shown a small increase in the rate of breast cancer for women taking mostly synthetic estrogens, but the interesting point is that the cancers that develop while patients are taking estrogens are of a better grade or are better differentiated, allowing for better treatment chances than those developing breast cancer while not on Hormone Replacement Therapy (HRT).

Besides falling estrogen levels, a large factor in these menopausal symptoms appears to lie with falling progesterone levels, which we will deal with shortly. Progesterone levels fall dramatically before menopause and as Dr. Jerilynn Prior points out, dropping levels of estrogen do not explain the symptoms of menopause. Western women tend to have higher estrogen levels than their eastern counterparts, likely due to diet that promotes obesity. With increased levels of an enzyme called aromatase found in fat cells that convert testosterone into estradiol, we would expect chubby men to have breast tissue and less body hair than thin athletic men. Since many women around the world do not experience the severe menopausal symptoms that western women do, the dramatic changes from such high levels of estrogen in the west may be the responsible factor.

Estrogen therapy can benefit women after menopause. Several studies looking at the benefits of estrogen and synthetic progestins have been done. The results have shown positive effects by raising HDL good cholesterol, but have also shown raised levels of triglycerides (blood fats) seen in the Postmenopausal Estrogen/Progestin Interventions (PEPI Trial) 1995 and Nurses' Health Study 1996. Also the Heart and Estrogen/Progestin Replacement Study (HERS) 1998 showed that women with pre-existent heart disease (50% of women in their 50's) had 1.5 times the number of cardiac events in the first year of Hormone Replacement Therapy (HRT).

The moral of the study may be that beginning HRT at the first signs of menopause may be important, and that such therapy should not be deferred for too many years. There may also be a subset of women that are predisposed to problems with estrogen that will be identified in the future. The Women's Health Initiative (WHI) is now under way and will answer some of our questions about the advantages of HRT or cardiovascular health in different groups of women.