Hormone Replacement Therapy in Women: A Look at the Options
Hormone replacement therapy (HRT) is sometimes used on a short-term basis to relieve unpleasant menopausal symptoms, such as hot flashes, vaginal dryness, and irritability. On a long-term basis, some women have used HRT based on the idea that it would reduce the risk of osteoporosis and heart disease. However, results of 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.
HRT can include the hormones estrogen alone, or the combination of estrogen and progesterone. 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 uterus removal (hysterectomy).
ERT can be administered in a variety of ways, including oral medications, patches, creams, and gels. 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.
Potential Side Effects of ERT
Estrogen Plus Progesterone (HRT)
Hormone replacement therapy (HRT) is treatment that combines ERT (estrogen only) 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 —This treatment provides estrogen for 25 days each month, adding progesterone on the last 10-14 days out of 25, followed by 3-6 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 days when no hormones are taken.
- Continuous-Cyclic HRT —This treatment provides estrogen every day, with progesterone added 10–14 days of each month. Like cyclic HRT, the main side effect is uterine bleeding (in the form of a period).
- Continuous-Combined HRT —This treatment 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. Breakthrough uterine bleeding occurs in some women on this schedule, but usually stops within the first year of therapy.
- Intermittent-Combined HRT —This treatment provides estrogen every day, with progesterone added intermittently in "on-off" cycles. The cumulative monthly dose of progestogen is about half of that of a continuous-combined pattern.
Potential Risks of HRT
Potential side effects and risks of HRT are basically the same as those listed for ERT. Long-term HRT may slightly, but significantly, increase the risk of strokes, blood clots, heart attacks, breast cancer, gallstones, and gallbladder disease. Adding progesterone however, eliminates the increased risk of endometrial cancer caused by estrogen alone. This applies to women who have not had their uterus removed.
Weighing Your Options
If you are currently taking estrogen or combined estrogen and progesterone or were thinking about starting, talk to your doctor about the right therapy for you.
National Institute on Aging
The American Congress of Obstetricians and Gynecologists
Canadian Women's Health Network
The Society of Obstetricians and Gynaecologists of Canada
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Last reviewed May 2016 by Michael Woods, MD Last Updated: 5/3/2016