What is Menopausal Hormone Therapy?

 

Menopausal hormone therapy (HT) provides women with the female hormones similar to those that decrease as they age, particularly at the menopause. When the primary female hormone, estrogen, is given alone, it is usually referred to as "ERT" (Estrogen Replacement Therapy). When a second type of hormone (progestin) is combined with estrogen, it is generally called "HT," formerly known as hormone replacement therapy. Estrogen is a female hormone that brings about changes in many organs in the body. Progesterone (the natural human progestin) is a female hormone that prepares the uterus for a pregnancy each month. During the transition to menopause, these hormone levels start to fluctuate, causing some uncomfortable symptoms. When the ovaries stop producing estrogen and progesterone, menstrual periods cease and the woman experience 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 interrupted sleep. 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 usually become apparent within weeks after treatment begins.


What are the Risks of Hormone Therapy?

 

Potential Long-Term Risks:

Cancer: There is concern that HT can increase the risk of some cancers. When estrogen is taken alone, it raises the risk of endometrial cancer (lining of the uterus). Adding progestin with estrogen can dramatically reduce this risk. Progestin is added to prevent the overgrowth (or hyperplasia) of cells in the lining of the uterus. Women who still have an intact uterus are generally given this combined therapy.

The National Institutes of Health's (NIH) Women's Health Initiative (WHI) stopped a major clinical trial early in July 2002, due to finding an increased risk of breast cancer in the group taking estrogen and progestin. After 5.2 years, estrogen plus progestin use resulted in a 26 percent increase in the risk of breast cancer or 8 more breast cancers each year for every 10,000 women. Women who had used estrogen plus progestin before entering the study were more likely to develop breast cancer than others, indicating that the therapy may have a cumulative effect. However, other similar studies have not found such smaller increases or no increased risk. A possible relationship between estrogen use and ovarian cancer remains unclear.

Breast Density: Taking both estrogen and progestin also can affect a woman's breast density. Increased breast density from HT makes it more difficult for a radiologist to read some mammograms, leading to the need for follow-up mammograms or breast biopsies. Increased density also is a concern because other studies have shown that women age 45 and older whose mammograms show at least 75% dense tissue are at increased risk for breast cancer. However, it is not known if increased breast density due to HT carries the same risk for breast cancer as having naturally dense breasts.

Heart Disease: In the past, taking HT (estrogen plus progestin) was thought to help protect women against heart disease. But recent findings from the WHI study showed that taking HT poses more risks than benefits. The study found that HT may increase a woman's risk for heart disease, stroke, deep vein thrombosis 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.

• Vaginal bleeding of an unknown cause
  
• Suspected breast cancer or history of breast cancer
  
• History of endometrial cancer or cancer of the uterus
  
• Chronic disease of the liver
  
• History of heart disease
  
• History of venous thrombosis (blood clots in the veins or legs, or in the lung). This includes women who have had thrombosis or blood clots during pregnancy or when taking birth control pills. Although the risk of blood clots in women is very low, HT increases the risk.
  

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 observational studies and the findings in the randomized controlled trial are so inconsistent with regard to the cardioprotective effects of estrogens. It has been proposed that women choosing to use estrogen in the observational studies had better health habits and medical care and were therefore less likely to develop heart disease than non-users. However, in most studies that adjusted for such confounding factors, there was still a protective effect of HT. 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 studies generally initiated HT at or near the menopause (for most women 45-55 years of age) for vasomotor symptoms (hot flashes). There are a number of reasons to believe that this difference may have been critical in producing opposite results.


What should I do now?

Women should be aware that estrogen is still the best available treatment for hot flashes and other menopausal estrogen deficiency symptoms. Women at risk for osteoporotic fractures may still benefit from estrogen prevention. The idea that estrogen helps prevent heart disease has been called into serious question, but, for younger women (40-55) with menopausal symptoms the risk/benefit ratio is still unclear. Therefore, women should discuss their options with their physician. Decisions to use or avoid HT should be individualized based on the particular woman’s symptoms, risk factors, and preferences.