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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• Hormone therapy facts
• What is menopause?
• Does menopause cause bone loss?
• What are estrogen therapy and hormone therapy (HT)?
• What are the side effects and risks of hormone therapy (HT)?
• How is hormone therapy (HT) prescribed?
• Who should take hormone therapy (HT)?
• Who should not take hormone therapy (HT)
• What medical checkups are advised for women on hormone therapy (HT)?
• What if a woman decides against hormone therapy (HT)?
• Hormone Therapy Index

What are estrogen therapy and hormone therapy (HT)?

Estrogen, in pill, patch, or gel form, is the single most effective therapy for suppressing hot flashes.

The term estrogen therapy, or ET, refers to estrogen administered alone. Because ET alone can cause uterine cancer (endometrial cancer) (see below), a progestin is administered together with estrogen in women who have a uterus (those who have not undergone a hysterectomy) to eliminate the increased risk. Thus, the term estrogen/progestin therapy, or EPT, refers to a combination of estrogen and progestin therapy, as is given to a woman who still has a uterus. This method of prescribing hormones is also known as combination hormone therapy.

The term hormone therapy (HT) is a more general term that is used to refer to either administration of estrogen alone (women who have had a hysterectomy), or combined estrogen/progestin therapy (women with a uterus).

All forms of hormone therapy (HT) that are FDA-approved for therapy of hot flashes are similarly effective in suppressing hot flashes.

What are the side effects and risks of hormone therapy (HT)?

Women can experience side effects during hormone therapy; these can be divided into more minor side effects, and more serious side effects. The more minor side effects are more common than the serious side effects, and are generally perceived by women as "annoying." These symptoms include:

• headaches,
• nausea,
• breast pain.

It is still controversial which of these side effects are due to the estrogen component as compared to the progesterone component. Therefore, if side effects persist for a few months, the doctor will often alter either the progesterone or the estrogen part of the hormone therapy (HT).

Contrary to common belief, recent research has confirmed that women who take commonly prescribed doses of hormone therapy (HT) are no more likely to gain weight than women not taking hormone therapy (HT). This is probably because menopause or aging itself is associated with weight gain, regardless of whether or not a woman takes hormone therapy.

The more serious health concerns for women undergoing hormone therapy (HT) include:

• Hormone therapy (HT) increases the risk of vein clots in the legs (deep vein thrombosis ) and blood clots in the lungs (pulmonary embolus) by about 2 or 3 fold. However, it is important to remember that these conditions are extremely rare in healthy women. Thus, the true increase in risk for healthy women is minimal. Women with a personal or family history of these blood clots should review this issue when considering hormone therapy (HT).

• Uterine Cancer (endometrial cancer): Research shows that women who have their uterus and use estrogen alone are at risk for endometrial cancer. Today, however, most doctors prescribe the combination of estrogen and progestin. Progestin protects against endometrial cancer. If there is a particular reason why a woman with a uterus cannot take some form of progesterone, her doctor will take sample tissue from her uterus (endometrial biopsy) to check for cancer annually while she is taking estrogen. Women without a uterus (women who have had a hysterectomy) have no risk of endometrial cancer.

• Breast cancer: Recent research indicates that hormone therapy (HT), and especially EPT, increases the risk of breast cancer, although the increase in risk is very small. For example, the Women's Health Initiative, a reliable large study of hormone therapy (HT) in menopausal women, predicted that there were approximately eight extra cases per 10,000 women who took hormone therapy (HT) for 1 year, compared to women taking a placebo pill. The increase in risk of breast cancer associated with hormone therapy (HT) likely increases with duration of use and is especially increased with five or more years of use.

• Heart disease: Even though hormone therapy (HT) lowers the bad LDL cholesterol and raises the good HDL cholesterol, hormone therapy (HT) increases the risk of heart attacks in women who already have heart disease, as well as in women who do not have known heart disease. Hormone therapy (HT) does not prevent heart attack based on recent research from the Women's Health Initiative.

• Abnormal vaginal bleeding: Women on hormone therapy (HT) are more likely than other postmenopausal women to experience abnormal vaginal bleeding. What is called "abnormal bleeding" depends on the type of hormone therapy (HT). With cyclic therapy, in which monthly bleeding is expected, bleeding is abnormal if it occurs when it is not expected or is excessively heavy or long in duration. With daily continuous therapy, irregular bleeding can last for six months to a year, therefore, irregular bleeding that lasts for more than a year is considered abnormal. When abnormal bleeding occurs, a doctor usually takes a sample of the lining of the uterus (endometrial biopsy) to rule out an abnormality or cancer in the uterus. This procedure is usually done in the office. After the evaluation is done, if nothing is found to be wrong, hormone therapy (HT) doses will often be adjusted to minimize further abnormal bleeding.

• Stroke: Hormone therapy (HT) slightly increased the risk of stroke in women studied in the Women's Health Initiative. The WHI predicted that there were 8 extra strokes per 10,000 women taking hormone therapy (HT) for one year, compared to women taking a placebo (sugar pill). Because of the possibility of increased breast cancer, stroke, and heart disease risks, women who have no major menopause symptoms may choose to avoid hormone therapy (HT). The effects of other types of hormone therapy (HT) (aside from the Women's Health Initiative types) on breast cancer risk are still unclear.