Hormone replacement therapy (HRT) is often used on a short-term basis for the relief of unpleasant menopausal symptoms such as hot flashes, vaginal dryness, and irritability. On a long-term basis, many women have used HRT based on doctors assumptions that it would reduce their risk of osteoporosis and heart disease . However, results of recent studies on estrogen replacement therapy (ERT) and estrogen plus progestin suggest that the risks of long-term HRT may outweigh the benefits for many women.
Along with new information about the risks of HRT, the number of HRT options has increased. So if you and your doctor decide that HRT may be right for you in the short- or long-term, how do you decide which therapy would be best?
HRT can include the hormones estrogen or progesterone, or a combination of both. If you're considering HRT for the first time, or want to talk to your doctor about changing the regimen you're presently on, here's a rundown of options.
Estrogen only: ERT
Therapies containing just estrogen are commonly referred to as "estrogen replacement therapy," or ERT. Because of the increased risk of endometrial cancer (lining of the uterus), long-term ERT is usually only offered to women who have had their uteruses removed through hysterectomy .
ERT can be administered in a variety of ways. "Systemic" ERT delivers estrogen so that it circulates throughout the body, whereas "local" ERT delivers estrogen to a particular area of the body, such as the vagina to treat vaginal dryness or vaginal atrophy.
Forms of systemic ERT include:
Oral medication: Premarin, Cenestin, Estratab, Menest, Ortho-Est, Ogen, Estrace
Skin patch: Alora, Climara, Esclim, Vivelle, Vivelle-Dot, Estraderm
Pellet implanted under the skin
Forms of local ERT include:
Vaginal creams: Premarin Vaginal Cream, Ogen Vaginal Cream, Estrace Vaginal Cream
Vaginal rings: Estring Vaginal Ring
Vaginal tablets: Vagifem Vaginal Tablet
Because only a small amount of estrogen circulates in the body with local ERT, these products typically only help with local symptoms such as vaginal dryness. They are usually not helpful in controlling other symptoms of menopause , such as hot flashes, or in preventing osteoporosis.
Potential side effects of systemic ERT include:
Uterine bleeding (if uterus is present)
Nausea or abdominal bloating
Fluid retention in extremities
Changes in the shape of the cornea of the eye, which sometimes makes contact lenses uncomfortable
Headache (sometimes migraine )
Increased breast density, which makes mammograms harder to interpret
Potential risks of systemic ERT include:
Ovarian and breast cancer
Enlargement of benign uterine tumors
Worsening of endometriosis
Endometrial cancer (if progesterone isn't taken with ERT)
Gallbladder problems, including gallstones (for orally administered ERT)
Pancreatitis in women with high triglyceride (fat) levels in the blood
Estrogen plus progesterone: HRT
Hormone replacement therapy (HRT) is treatment that combines ERT with a form of the hormone progesterone. This may consist of natural progesterone or a synthetic progesterone, called progestin. Both forms are also called progestogens.
There are several HRT schedules and methods of delivery available, including:
Cyclic HRT - provides estrogen for 25 days each month, adding progesterone on the last 1014 days out of 25, followed by 36 days of no therapy. This way, both hormones are "cycled." Cyclic HRT may cause uterine bleeding (a menstrual period) when the progesterone cycle ends. Hot flashes are also more likely to return on the 36 days when no hormones are taken.
Continuous-cyclic HRT - provides estrogen every day, with progesterone added 1014 days of each month. Like cyclic HRT, the main side effect of this type of therapy is uterine bleeding (in the form of a period), which occurs in about 80% of women on this schedule when the progesterone cycle ends. This form of HRT is available in oral medication (Premphase) or skin patch (CombiPatch).
Continuous-combined HRT - provides both estrogen and progesterone every day. The daily dose of progesterone is much lower than the daily dose in cyclic therapy, which may result in a lower total dose over the course of the month. Uterine bleeding occurs in about 50% of women on this schedule, but usually stops within the first six months of therapy. This is available as oral medication (Prempro, Femhrt, Activella) or skin patch (CombiPatch).
Intermittent-combined HRT - provides estrogen every day, with progesterone added intermittently in cycles of three days on, three days off. The cumulative monthly dose of progestogen is about half of that of a continuous-combined pattern. This is available as oral medication (Ortho-Prefest).
Risks of HRT
Potential side effects of HRT are basically the same as those listed above for ERT, as are many of the risks. Long-term HRT may increase the risk of strokes , blood clots, heart attacks, and invasive breast cancers, according to the most recent Womens Health Initiative study. Adding progesterone, however, eliminates the increased risk of endometrial cancer caused by estrogen alone. This applies to women who have not had their uteruses removed via a hysterectomy.
The result of the recent Womens Health Study has raised a lot of serious questions about the safety of HRT. Nevertheless, if you are currently taking estrogen or combined estrogen and progesterone or were thinking about starting, talk to your doctor before making any final decisions about what to do.
American College of Obstetricians and Gynecologists
Menopausal Hormone Therapy Information
by Amy Scholten, MPH
American College of Obstetricians and Gynecologists.
Hormone replacement therapy. National Institute on Aging.
Menopause Guidebook , by the North American Menopause Society, 2001.
North American Menopause Society.
National Institutes of Health.
USP Database Estrogens (Systemic) Estrogens (Vaginal) Progesterone.
Last reviewed August 2006 by Jill Landis, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.