Welcome to Estrogen Replacement Therapy &
Hormone Replacement Therapy Resource Guide
Knowledge is Power Resource Guide, providing free information to get you on the road to health and wellness today by using knowledge obtained from web medical doctor
Hormone replacement therapy (HRT), also known as Estrogen Replacement Therapy (ERT) is medication containing one or more female hormones, commonly estrogen plus progestin (synthetic progesterone). Some women receive estrogen-only therapy (usually women who have had their uterus removed).
Hormone replacement therapy is most often used to treat symptoms of menopause such as "hot flashes," vaginal dryness, mood swings, sleep disorders, and decreased sexual desire. This medication may be taken in the form of a pill, a patch, or vaginal cream.
Based on early studies, many physicians used to believe that Hormone replacement therapy might be beneficial for reducing the risk of heart disease and bone fractures caused by osteoporosis (thinning of the bones) in addition to treating menopausal symptoms. The results of a new study, called the Women's Health Initiative (WHI), has led physicians to revise their recommendations regarding Hormone and Estrogen replacement therapy.
The WHI, started in 1993, has enrolled 161,809 women, ages 50 - 79, in 40 different medical centers. Part of the study was intended to examine the health benefits and the risks of hormone replacement therapy, including the risk of developing breast cancer, heart attacks, strokes, and blood clots.
In July 2002, one component of the WHI, which studied the use of estrogen and progestin in women who had a uterus, was stopped early because the health risks exceeded the health benefits. The main reason for stopping the estrogen-progestin study was because of a 26% increase in breast cancer.
In March 2004, a second component of the WHI, which studied estrogen-only therapy in women who no longer had a uterus (see hysterectomy), was stopped early. This was primarily because of an increase in the risk for strokes.
The information below includes detailed information from the WHI study about each risk. A summary follows at the end.
During menopause, the amount of estrogen produced by a woman's ovaries drops. These naturally occurring low estrogen levels may cause symptoms that include hot flashes, sleep problems, mood swings, and vaginal dryness.
Most women experience relief from the hot flashes, sleep difficulties, and vaginal dryness within a few-weeks of taking Hormone replacement therapy. Short-term use (2-4 years) of Hormone replacement therapy to treat the symptoms of menopause still appears to be safe at this time. Usually, hot flashes and night sweats are less severe after a couple of years -- especially if Hormone replacement therapy is tapered gradually.
Estrogen helps decrease "bad" cholesterol and increase "good" cholesterol in the bloodstream. Because lower levels of "bad" cholesterol and higher levels of "good" cholesterol are associated with a decreased risk of heart disease, researchers thought that Hormone replacement therapy should lower risk by changing these levels.
However, the WHI has shown that this is not true. The number of heart attacks actually increased 29% among women taking estrogen and progestin. Put another way, WHI researchers estimate that 37 of every 10,000 women taking Hormone replacement therapy will have a heart attack, while 30 in 10,000 not taking Hormone replacement therapy will have a heart attack.
The Heart Estrogen/progestin Replacement Study (HERS) published earlier in 2002 also showed no benefit for the heart of taking estrogen and progestin. These women were followed for almost 7 years.
Hormone replacement therapy should not be given strictly for the prevention of high cholesterol or heart disease. Generally, lifestyle changes and medications to lower cholesterol and control blood pressure are recommended for those conditions.
The WHI study showed a 41% increase in strokes among the women taking estrogen/progestin. For every 10,000 women taking Hormone replacement therapy, 29 will have a stroke, compared with 21 in 10,000 women not taking Hormone replacement therapy.
An increased risk of stroke was also seen in the estrogen-only therapy.
Blood Clots/Thromboembolic Disease
The increased risk of blood clots from taking estrogen has been recognized for years. Generally, this risk has been associated with the use of oral contraceptives that contain high doses of estrogen. It is further increased for women who smoke cigarettes.
The WHI study confirmed an increase in the number of blood clots in women taking estrogen/progestin. For every 10,000 women taking Hormone replacement therapy, 34 will develop clots in their lungs or legs, while 16 in 10,000 not taking Hormone replacement therapy will develop blood clots.
A woman's body produces less estrogen during and after menopause, which may affect her bone strength. The WHI study showed that women taking Hormone replacement therapy had 34% fewer hip fractures and 24% fewer fractures than women not receiving hormones.
However, the short-term use of "estrogen replacement therapy" to relieve symptoms at the time of menopause does little to prevent fractures in women when they reach 75-80 years of age. Women who take estrogen to maintain bone density must continue taking estrogen because the beneficial effects on bones disappear when it is discontinued.
Women who are considering taking Hormone replacement therapy to prevent osteoporosis should discuss with their physician their individual risk of coronary heart disease, stroke, blood clots, and breast cancer.
Instead, supplemental calcium and increasing vitamin D intake may be recommended for some women to help prevent and treat loss of bone mass. Other lifestyle changes, such as adding an exercise regimen to your routine and not smoking, may help in the prevention and treatment of osteoporosis as well.
In addition, there are some medications available specifically for prevention and treatment of osteoporosis. These include risedronate, calcitonin, etidronate, and alendronate.
The WHI estrogen/progestin trial was stopped primarily because of a 26% increased risk of breast cancer found in women taking hormone therapy. For every 10,000 women taking estrogen/progestin, 38 will develop invasive breast cancer; of 10,000 women not taking Hormone replacement therapy, 30 will develop the disease.
The second component of the WHI study, which looked at estrogen alone in women who no longer have a uterus, did not find any increased risk of breast cancer.
Uterine Cancer/Endometrial Cancer
Taking estrogen alone causes the lining of the uterus to grow. The risk for endometrial cancer is six to eight times higher in women who take estrogen, compared with those who do not.
Progestin works to decrease the lining of the uterus. For women who still have their uterus, most doctors prescribe progestin (a synthetic progesterone) to counteract the effect of the estrogen.
The WHI study did not find any difference in endometrial cancer rates between the women who took hormones and those who did not. Depending on the form of Hormone replacement therapy, taking progestin may cause bleeding similar to a period. This combination of estrogen and progesterone may be in the form of one pill, or it may be two separate pills.
In another study, published by the National Cancer Institute in 2002, women who use estrogen therapy alone have an increased risk of developing ovarian cancer. This risk increases with the number of years a woman uses estrogen.
For women who used estrogen for 20 or more years, the risk of ovarian cancer was three times that of women who did not use estrogen.
This study did not have enough women to assess the potential risk of an estrogen/progestin combination on the risk of ovarian cancer.
The WHI study found a 37% lower risk of colon cancer in women who took estrogen/progestin than in women not on Hormone replacement therapy. For every 10,000 women taking estrogen/progestin, 10 will develop colon cancer; of 10,000 women not taking Hormone replacement therapy, 16 will develop the disease. This is a relatively new finding, and further studies are needed to confirm these results.
Several studies have shown that women who use estrogen/progestin therapy are at increased risk of developing gallstones.
Hormone replacement therapy has not been found to improve or reduce the incidence of incontinence after menopause.
Studies have shown that women who suffer from common vasomotor symptoms of menopause, mood swings, and sleep problems benefit from Hormone replacement therapy in the overall quality of their life.
However, there is no scientific evidence that Hormone replacement therapy is helpful in the treatment of major depression.
Studies have not shown that Hormone replacement therapy slows down the symptoms of Alzheimer's disease. Studies are ongoing as to whether there is any benefit to Hormone replacement therapy with regard to other memory loss.