Excerpt from webmd.com
What Is Hormone Replacement Therapy?
Hormone replacement therapy is used to supplement the body with either estrogen alone or estrogen and progesterone in combination during and after menopause. 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), HRT 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 when they are moderate to severe.
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 the 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 Replacement Therapy?
There are two main types of hormone replacement 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.
• Progesterone/Progestin-Estrogen Hormone Therapy: Also called combination therapy, this form of HRT 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 that can occur when combination HRT is used. The current recommendation is to take the lowest dose of hormone therapy for the shortest time possible. Like all prescription medications, HRT 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
Who Shouldn’t Take Hormone Replacement Therapy?
Hormone replacement therapy 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
Cigarette smokers should consider stopping tobacco use before taking HRT.
What Are the Side Effects of Hormone Replacement Therapy?
Like almost all medications, hormone replacement therapy has side effects. The most common side effects are:
• Monthly bleeding
• Irregular spotting
• Breast tenderness
Less common side effects of HRT include:
• Blood clots and stroke (rare, but the most serious risk)
• Fluid retention
• Headaches (including migraine)
• Skin discoloration (brown or black patches)
• Increased breast density (making mammogram evaluation more difficult)
• Skin irritation under estrogen patch
How Can I Reduce the Side Effects of Hormone Replacement Therapy?
Adjusting either the dosage or the form of the medication you are taking can often reduce side effects of HRT. However, you should never make changes in your medication or stop taking it without first consulting your doctor.