About Hormone Therapy
What is menopausal hormone therapy?Menopausal hormone therapy (HT) provides women with the female hormones that decrease after menopause. When the hormone estrogen is given alone, it is usually referred to as estrogen replacement therapy (ERT). When the estrogen is combined with the hormone progestin or progesterone, it is generally called hormone therapy (HT). Estrogen is a female sex hormone that brings about changes in the body. Progesterone is a female hormone that prepares the uterus for a pregnancy each month. During the transition to menopause ("perimenopause") these hormone levels start to fluctuate, causing some uncomfortable symptoms. When the ovaries stop producing estrogen and progesterone, menstrual periods cease and the woman has experienced menopause.
What are the benefits of hormone therapy?Hormone therapy has been used to relieve the short-term symptoms of menopause, such as hot flashes, sweats and sleep disturbances. There is some evidence that it may be helpful in preventing colon cancer, age-related vision loss, coronary heart disease and fractures. Some studies show decreases in all-cause mortality as well.
What are the risks of hormone therapy?Short-term side effects: Some women report side effects including unusual vaginal discharge and bleeding, headaches, nausea, fluid retention and swollen breasts. Short-term benefits or side effects should become apparent within weeks or months after treatment begins.
Potential long-term risks:Cancer: There is concern that HT can increase the risk of some cancers such as endometrial cancer (lining of the uterus). Adding in progestin with estrogen can dramatically reduce this risk.
The National Institutes of Health's (NIH) Women's Health Initiative (WHI) stopped a major clinical trial in July 2002, due to finding an increased risk of breast cancer from HT with estrogen and progestin. The increased risk of breast cancer appeared after four years of hormone use.
Heart Disease: In the past, taking HT (estrogen plus progestin) was thought to help protect women against heart disease. But recent findings from the Women's Health Initiative (WHI) study showed that taking HT poses more risks than benefits. The study found that HT could increase a woman's risk for heart disease, stroke, and pulmonary embolism (blood clot in the lung), as well as breast cancer. Hormones are not recommended for women with heart disease or for women who have had a stroke.
What may be some of the reasons for the inconsistencies in the findings of HT studies over the years?It is unclear why the results of many years of prior basic and observational trials and the more recent studies are so inconsistent as to be essentially opposite, especially with regard to the cardio-protective effects of estrogens. It has been proposed that the critical difference between the WHI study and prior studies showing cardio-protection is due to the fact that women choosing to use estrogen in those studies had better health habits and medical care and were thus less likely to develop heart disease than non-users. (It seems more likely that the inconsistency in question was due to differences in populations studied). Women in the WHI were 50-79 (average 62.7) years old, whereas women in the observational and epidemiological studies generally initiated HT at or near the menopause (for most women 45-55 years of age) for vasomotor symptoms.
Do you want to learn more about hormone therapy?The North American Menopause Society's (NAMS) mission is to promote the health and quality of life of women through an understanding of menopause. Click here to view the NAMS hormone position statement.