Hormone Replacement Therapy

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Hormone Therapy

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In the past, hormone therapy (HT) was widely recommended for the treatment of menopausal symptoms as well as in the prevention of osteoporosis and heart disease. A large study known as the Women's Health Initiative (WHI) shed new light on how HT is viewed.

According to the WHI study results, long term combination HT increases the risk of heart disease, breast cancer, blood clots and stroke. Estrogen-only HT was found to increase the risk of blood clots and stroke but did not appear to worsen a woman's chances of getting breast cancer or heart disease.

What Is Hormone Therapy?

Hormone therapy is a treatment that is used to supplement the body with either estrogen alone or estrogen and progesterone in combination. Estrogen and progesterone are hormones that are produced by a woman's ovaries. When the ovaries no longer produce adequate amounts of these hormones (as in menopause), HT can be given to supplement the body with adequate levels of estrogen and progesterone.

Why Does the Body Need Estrogen and Progesterone?

Estrogen and progesterone together thicken the lining of the uterus, preparing it for the possible implantation of a fertilized egg. Estrogen also influences how the body uses calcium, an important mineral in the building of bones, and helps maintain healthy levels of cholesterol in the blood. Estrogen also keeps the vagina healthy.

As menopause nears, the ovaries reduce most of their production of these hormones. Lowered or fluctuating estrogen levels may cause menopause symptoms such as hot flashes, and medical conditions such as osteoporosis. Hormone therapy helps to replenish the estrogen, relieving some of the symptoms of menopause and helping to prevent osteoporosis.

Why Is Progesterone Taken?

Progesterone is used along with estrogen in women who still have their uterus. In these women, if taken without progesterone, estrogen increases a woman's risk for cancer of the endometrium (the lining of the uterus). During a woman's reproductive years, endometrial cells are shed during menstruation. When the endometrium is no longer shed, estrogen can cause an overgrowth of cells in the uterus, a condition that can lead to cancer.

Progesterone reduces the risk of endometrial cancer by making the endometrium shed each month. As a result, women who take progesterone may have monthly bleeding. Monthly bleeding can be lessened and, in some cases, eliminated by taking progesterone and estrogen together continuously. Women who have had a hysterectomy (removal of the uterus through surgery) usually do not need to take progesterone.

What Are the Types of Hormone Therapy?

There are two main types of hormone therapy:

• Estrogen Therapy: Estrogen is taken alone. Doctors most often prescribe a low dose of estrogen to be taken as a pill or patch every day. Estrogen may also be prescribed as a cream. You should take the lowest dose of estrogen needed to relieve menopause symptoms and/or to prevent osteoporosis.
• Progesterone/Progestin-Estrogen Hormone Therapy: Also called combination therapy, this form of HT combines doses of estrogen and progesterone (progestin is a synthetic form of progesterone). Estrogen and a lower dose of progesterone also may be given continuously to prevent the regular, monthly bleeding can occur when combination HT is used. The current recommendation is to take the lowest dose of hormone therapy for the shortest time consistent with the reason the woman is taking the therapy. Like all prescription medications, HT should be re-evaluated each year.

What Menopause Symptoms Can Estrogen Relieve?

Estrogen is prescribed to relieve:

• Hot flashes.
• Vaginal dryness that can result in painful intercourse.
• Other problematic symptoms of menopause, such as night sweats and dry, itchy skin.

Other benefits of taking HT include:

• Reduced risk of developing osteoporosis and reduced risk of bone breakage.
• Improvement of mood and overall sense of mental well-being in some women.
• Decreased tooth loss.
• Lowered risk of colon cancer.

What Are the Risks of Taking HT?

While HT helps many women get through menopause, the treatment (like any prescription or even non-prescription medicines) is not risk-free. Known health risks include:

• An increased risk of endometrial cancer (if a woman still has her uterus and is not taking progesterone along with estrogen).
• Increased risk of blood clots and stroke.
• Increased risk of breast cancer in women taking estrogen-progestin combination therapy for extended periods of time. Estrogen alone has not been shown to increase the risk of breast cancer in the estrogen-alone arm of the Women's Health Initiative (WHI) study.
• According to the WHI, an increased risk of heart disease in women taking long-term estrogen-progestin combination therapy. Estrogen alone has not been shown to increase the risk of heart disease in the estrogen-alone arm of the Women's Health Initiative (WHI) study. NOTE: newer studies suggest that the findings of an increased heart disease risk for those on long-term combination therapy may be more relevant to women of more advanced age. These newer studies also showed a decrease in the risk of heart disease when HT was started in younger women (those just beginning menopause).

Every day doctors are learning more and more about HT. Talk to your doctor if you have questions or concerns.

What Are Some Commonly Used Postmenopausal Hormones?

The following charts list the names of some, but not all, postmenopausal hormones.

Who Shouldn't Take HT?

HT is not usually recommended for women who have:

• Active or past breast cancer.
• Recurrent or active endometrial cancer.
• Abnormal vaginal bleeding.
• Recurrent or active blood clots.
• History of stroke.
• Liver disease.
• Known or suspected pregnancy.

What Are the Side Effects of HT?

Like almost all medications, hormone therapy has side effects. The most common side effects are:

• Monthly bleeding
• Irregular spotting
• Breast tenderness

Less common side effects of hormone therapy include:

• Blood clots and stroke (rare, but the most serious risk).
• Fluid retention.
• Headaches (including migraine).
• Dizziness.
• Skin discoloration (brown or black patches).
• Increased breast density making mammogram interpretation more difficult.
• Skin irritation under estrogen patch.

How Can I Reduce These Side Effects?

Adjusting either the dosage or the form of the medication you are taking can often reduce side effects of HT. However, you should never make changes in your medication or stop taking it without first consulting your doctor.

How Can I Know If HT Is Right for Me?

There are many factors to consider when deciding whether to take hormone therapy, including your current health status and medical history. Discuss your risk factors and medical history with your doctor. You should also weigh the risks and benefits of hormone therapy and consider other treatments.

To get an idea if hormone therapy could be right for you, take WebMD's Quiz.

How Long Should I Take HT?

Since research on HT is ongoing, women should revaluate their treatment plans each year. Discontinue HT (under your health care provider's guidance) if you develop a medical condition that would make it less safe for you.

Can HT Prevent Heart Disease?

Results from the Women's Health Initiative (WHI) study revealed that the overall rate of heart disease events in postmenopausal women with established heart disease on estrogen-progestin or estrogen alone was not reduced. The results showed that the therapy actually increased the risk of heart disease in the women on combination therapy.

A newer study, published in the January/February 2006 issue of The Journal of Women's Health showed that the risk of heart disease demonstrated in the WHI may be related more to the advanced age of the participants as opposed to the HT itself. The study also found that HT given to younger women, at the onset of menopause, appeared to decrease the risk of heart disease.

Another study, published in the February 13, 2006 issue of the Archives of Internal Medicine, looked at nearly 11,000 women aged 50 to 79 taking only estrogen. Researchers reported no overall difference in heart attack risk among women who took the hormone and those who did not. In addition, there appeared to be a lower overall risk of heart disease in the women who began taking the estrogen between the ages of 50 and 59, suggesting a heart-healthy benefit to taking the therapy, if begun at a younger age.

More studies are underway to investigate the relationship between HT and heart disease.

Based on the WHI Study Results, Should I Stop Taking HT?

It's important that you do not make any abrupt changes to your HT without consulting your doctor. He or she can discuss with you the benefits and risks of HT based on your individual circumstances.

The National Heart, Lung and Blood Institute (NHLBI), which sponsored the study in collaboration with other units of the National Institutes of Health (NIH), has the following recommendations for women who may have questions about the long-term use of HT:

• First, the therapy should not be continued or started to prevent heart disease. Women should consult their doctor about other methods of prevention, such as lifestyle changes, and cholesterol- and blood pressure-lowering drugs.
• Second, for osteoporosis prevention, women should consult their doctor and weigh the benefits against their personal risks for heart attack, stroke, blood clots, and breast cancer. Alternate treatments also are available to prevent osteoporosis and fractures.
• Third, women should keep up with their regular schedule of mammograms and breast self-examinations.
• Finally, while short-term use was not studied, women taking the therapy for relief of menopausal symptoms may reap more benefits than risks. Women should talk with their doctor about their personal risks and benefits.

Reviewed by Holly L. Thacker, M.D., F.A.C.P., Director of The Women's Health Center at The Cleveland Clinic, January 2006.

Medically reviewed by Cynthia Haines, MD, February 2006.

SOURCES: The National Institutes of Health. Women's Health Initiative. The Journal of Women's Health, January/February 2006 issue. WebMD Medical Reference provided in collaboration with The Cleveland Clinic: "Is Hormone Therapy Helpful After All."