Oral (pills or tablets)
||Cenestin, Enjuvia, Premarin
Enjuvia contains plant-based, rather than animal-based,
estrogen. Risks and benefits are thought to be the same for both types of
Transdermal (patch placed on the skin that releases estrogen continuously)
||Alora, Estraderm, Vivelle-Dot
Vaginal ring (inserted high into the vagina; releases estrogen continuously for 3 months)
Skin cream (applied daily to the legs, thighs, or calves)
Skin gel (applied daily to an arm from wrist to shoulder)
How It Works
Estrogen replacement therapy (ERT)
estrogen level in your body. Estrogen impacts multiple
systems of the body.
When given through an estrogen patch,
vaginal ring, or skin cream or gel (transdermal estrogen), estrogen enters the
bloodstream directly, without passing through the liver. The estrogen in pills
must be processed by the liver before entering the bloodstream, which puts
stress on an impaired liver.
Low-dose vaginal estrogen affects
only the urinary and genital area. For more information, see
Low-Dose Vaginal Estrogen for Dryness and Atrophy.
Patch warning. Direct
sunlight or high heat can increase, then decrease, the amount of hormone released
from a patch. This can give you a big dose at the time and leave less hormone
for the patch to release later in the week. Avoid direct
sunlight on the hormone patch. Also avoid using a tanning bed, heating pad,
electric blanket, hot tub, or sauna while you are using a hormone patch.
Why It Is Used
Estrogen replacement therapy (ERT)
is used to increase estrogen levels in
postmenopausal women who have no uterus. This
treatment may help prevent
osteoporosis, and colon cancer.
their 20s, 30s, and 40s who experience early menopause after having their
ovaries removed (oophorectomy) or because of other medical reasons typically
take ERT to reduce their risk of early bone loss and osteoporosis.
Historically, women have continued using ERT for years beyond menopause. Some
women now discontinue ERT around the age of menopause.
a uterus who take estrogen also need the hormone
progestin to prevent the estrogen from overgrowing the
uterine lining, which can lead to
endometrial (uterine) cancer. Estrogen-progestin is
hormone replacement therapy (HRT).
Do not use estrogen treatment if you:
Talk to your doctor about your risks versus benefits if you have a family history of breast cancer,
stroke, blood clots, or endometrial cancer.
How Well It Works
Systemic estrogen replacement
therapy (ERT) affects your entire body and reverses the effect of low estrogen.
Systemic ERT may:
- Reduce the
frequency and severity of
- Improve moodiness and sleep problems related to hormone changes.1
- Maintain the lining of the
vagina, reducing irritation.
- Increase skin
collagen levels, which decline as estrogen levels
decline. Collagen is responsible for the stretch in skin and
- Help prevent postmenopausal
osteoporosis by slowing bone loss and promoting some
increase in bone density.4
- Reduce the risk of dental problems, such as tooth loss and
Low-dose estrogen. Researchers are
studying the effects of low-dose estrogen therapy. Low-dose estrogen may keep
bones strong and may relieve hot flash symptoms.5 But
the long-term risks of taking low-dose estrogen are not yet known.
Risks of estrogen replacement therapy
replacement therapy (ERT) may increase the risk of health problems in a small number of women. This
increase in risk depends on your age, your personal risk, and when ERT is started.1 Talk with
your doctor about these risks. Using ERT may increase your risk of:
Side effects that can occur
with all forms of estrogen but are more common with oral estrogen (and less
common with a patch, cream, gel, or vaginal ring) include:
Some of these side effects, such as headaches, nausea,
fluid retention, weight gain, and breast tenderness, may go away after a few
weeks of use.
The estrogen patch (transdermal estrogen) may cause
An estrogen ring must be replaced every 3 months.
If the ring falls out at any time during the 3-month treatment period, you may
rinse it with lukewarm water and reinsert it.
See Drug Reference
for a full list of side effects. (Drug Reference is not available in all
What To Think About
In the Million Women Study of British women ages 50 to 64, taking
any form of estrogen for 10 years increased breast
cancer risk. The Women's Health Initiative study did not show this increased
risk for women taking estrogen alone (ERT) for 7 years.3 So taking long-term ERT probably slightly increases breast
cancer risk, and taking it with progestin (HRT) further increases breast cancer
risk.2 But only women who have had a
hysterectomy can take estrogen alone without also
worrying about endometrial (uterine) cancer risk.2
ERT use slightly increases the risk of stroke.
For this reason, the
Women's Health Initiative ERT trial was stopped sooner
than originally planned. In this large trial, women using ERT had no change in
heart disease risk, had fewer hip fractures (a sign of estrogen's
bone-protecting effect), and (unlike the larger Million Women Study) had no
increase in breast cancer risk during the study's nearly 7 years of ERT
If you are taking ERT after
early menopause caused by a surgical hysterectomy, talk with your doctor about
long-term ERT risks and benefits.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
North American Menopause Society (2010). Estrogen and
progestogen use in postmenopausal women: 2010 position statement of the
North American Menopause Society. Menopause, 17(2):
242-255. Also available online: http://www.menopause.org/PSht10.pdf.
Million Women Study Collaborators (2003). Breast
cancer and hormone-replacement therapy in the Million Women Study.
Lancet, 362(9382): 419-427.
Women's Health Initiative Steering Committee (2004).
Effects of conjugated equine estrogen in postmenopausal women with
hysterectomy. JAMA, 291(14): 1701-1712.
Speroff L, Fritz MA (2005). Menopause and the
perimenopausal transition. In Clinical Gynecologic Endocrinology and Infertility, 7th ed., pp. 621-688. Philadelphia:
Lippincott Williams and Wilkins.
Bachmann GA, et al. (2007). Lowest effective
transdermal 17beta-estradiol dose for relief of hot flashes in postmenopausal
women. Obstetrics and Gynecology, 110(4):