What is hormone replacement therapy?

As a woman approaches menopause, the production of estrogen and progesterone fluctuates and then decreases significantly. Symptoms such as hot flashes often result from the changing hormone levels. After a woman's last menstrual period, when her ovaries make much less estrogen and progesterone, some symptoms of menopause might disappear, but others may continue.

To help relieve these symptoms, some women use hormones. This approach is known as hormone replacement therapy or HRT. As with all medication, women should discuss the potential risks and benefits with her health care provider before administering.

How is hormone replacement therapy administered?

Hormone therapy can be given in a variety of methods, including the following:

Estrogen pills

Estrogen pills can either be taken every day or for 25 days each month. Women who have had a hysterectomy (uterus removed) can take estrogen alone, while those who have not may take a combination pill (estrogen and progestin).

Estrogen/Progestin pills

There are two methods—the continuous method and the cyclic method—for taking estrogen and progestin. In the continuous method, a pill that contains both estrogen and progestin is taken daily. Occasionally, irregular bleeding may occur.

The cyclic method involves taking estrogen and progestin separately—with estrogen taken either every day or daily for 25 days of the month and progestin taken for 10 to 14 days of the month. This may cause monthly "withdrawal" bleeding.

Estrogen and Estrogen/Progestin skin Patches

Using this method, a patch is applied to the skin of the abdomen or buttocks for 3 or 7 days. The patch is then discarded and a new one is applied. The patch can be left on at all times, even while swimming or bathing, and either the estrogen, or estrogen/progestin combination is delivered through the skin into the bloodstream. Progestin can be taken in a pill form with the patch. The patches may cause monthly bleeding.

Estrogen cream

Estrogen cream is inserted into the vagina or used locally around the vulva to help with vaginal dryness and urinary problems.


A class of drugs called selective estrogen receptor modulators (SERMs).

For women who are appropriate candidates, this type of therapy can often be customized to provide the most benefits with the least side effects. It is important for women to talk with their health care providers about any discomfort or menstrual symptoms experienced with hormone replacement treatment, as treatment approaches and dosages can be adjusted.