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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.
MENOPAUSE SYMPTOMS
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.
HEART DISEASE
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.
STROKES
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
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.
OSTEOPOROSIS
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.
BREAST CANCER
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.
OVARIAN CANCER
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.
COLON 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.
GALLBLADDER DISEASE
Several studies have shown that women who use estrogen/progestin
therapy are at increased risk of developing gallstones.
URINARY INCONTINENCE
Hormone replacement therapy has not been found to improve
or reduce the incidence of incontinence after menopause.
DEPRESSION
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.
ALZHEIMER'S DISEASE
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.
SIDE EFFECTS FROM Hormone replacement therapy
As with all medicines, there are side effects associated
with Hormone replacement therapy. Some women taking Hormone
replacement therapy may experience water retention, bloating,
nausea, breast soreness, mood swings, and headaches. Changing
the dosage or the form of Hormone replacement therapy may
help to alleviate these side effects.
Some women have irregular bleeding when they start taking
Hormone replacement therapy, but changing the dosage often
eliminates this side effect.
SUMMARY OF RISKS/BENEFITS
The WHI study shows relatively small absolute increases in
the risk of heart disease, breast cancer, blood clots, and
stroke to an individual woman. However, when the entire population
of postmenopausal women and the number of years a woman may
be on Hormone replacement therapy are considered -- the number
of strokes, heart attacks, breast cancer cases, and blood
clots appears to outweigh the protective effect of Hormone
replacement therapy on bones.
Some women may still wish to consider Hormone replacement
therapy for short-term treatment of menopausal symptoms. The
key is to weigh the risks associated with taking Hormone replacement
therapy against a particular woman's risk of heart disease
or osteoporosis without taking Hormone replacement therapy.
Every woman is different. Therefore, your entire medical history
should be evaluated individually when considering Hormone
replacement therapy.
FORMS OF Hormone replacement therapy
Hormone replacement therapy is available in various forms,
including pills, patches, and vaginal creams. Your health
care provider will start you on a regimen that is best suited
for you. It may be necessary to try more than one regimen
before finding the one that works best for you.
Cyclic hormone therapy is often recommended. With this therapy,
estrogen is taken in pill form for 25 days, with progestin
added somewhere between days 10 - 14. The estrogen and progestin
are taken together for the remainder of the 25 days. Then,
no pills are taken for 3 - 5 days. There will be monthly bleeding
with cyclic therapy.
Continuous, combined therapy is where estrogen and progestin
are taken together every day. When this therapy is started,
or when switching from cyclic to continuous therapy, women
may experience irregular bleeding. Most women stop bleeding
within one year after starting this therapy.
Hormone replacement therapy is also available as a patch which
is applied to the abdomen or the thigh. This patch allows
the estrogen to be absorbed through the skin into the bloodstream.
Some women prefer this method because they do not have to
take pills.
Vaginal cream containing estrogen may be given to women for
vaginal dryness. The cream is usually given along with one
of the other forms of Hormone replacement therapy because
the cream may not relieve many of the other symptoms and does
not appear to protect against bone disease.
Additional medications may be recommended for some women
with severe symptoms from menopause, or women who are at very
high risk for osteoporosis or heart disease. One of these
supplemental drugs might be androgen, a male hormone given
with estrogen to relieve severe hot flashes.
HEALTHY LIFESTYLE
In addition to taking Hormone replacement therapy, there
are other things that can help women adjust to the changes
in life during menopause. Eating healthy foods and getting
regular exercise will also help to decrease bone loss and
maintain healthy heart muscle.
CALLING YOUR DOCTOR
Talk to your doctor about the risks and benefits of taking
estrogen and progestin.
If you experience any of the following side effects, call
your doctor immediately:
- sudden, severe headache
- sudden, severe vomiting
- sudden partial or complete loss of vision
- speech problems
- dizziness or faintness
- weakness or numbness of an arm or a leg; crushing chest
pain or chest heaviness
- coughing up blood
- sudden shortness of breath
- calf pain
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