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Hormone therapy

​​​​​​​​Hormone therapy is an option for treating symptoms resulting from your body no longer making key chemicals.

The therapy has benefits and risks, so you should consult with your health care provider about whether it is right for you.

Marshfield Clinic's Obstetrics and Gynecology team provides complete women's health solutions.​

Understanding Hormone Therapy

When a woman's body no longer makes estrogen, hormone therapy may be an option. But, hormone therapy (HT), in which estrogen and progestin (a synthetic progesterone) are used in combination, has been controversial over the years.

Picture of two elderly women, smiling

To learn more about women's health, and specifically hormone therapy, the National Institutes of Health (NIH) did a study called the Women's Health Initiative (WHI) beginning in 1991. The study involved more than 161,000 generally healthy postmenopausal women.

The study was designed to test the effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, and breast and colorectal cancer in women.

The study had 2 arms:

  • The estrogen-plus-progestin study of women with a uterus


  • The estrogen-alone study of women without a uterus

Women with a uterus were given progestin in combination with estrogen, which is known to prevent endometrial cancer. All women were randomly assigned to either the hormone medication being studied or to placebo (inactive substance). Compared with placebo, the estrogen plus progestin treatment resulted in:

  • Small increase in risk of heart attack (in women younger than 60 when started in perimenopause, combined hormone therapy may reduce risk of heart attack)

  • Small increase in risk of stroke

  • Small increase in risk of blood clots

  • Small increase in risk of breast cancer

  • Reduced risk of colorectal cancer

  • Fewer fractures

  • No protection against mild cognitive impairment and increased risk of dementia (study included only women 65 and older)

Compared with the placebo, treatment with estrogen alone resulted in:

  • No difference in risk for heart attack

  • Increased risk of stroke

  • Increased risk of blood clots

  • Reduced risk of breast cancer

  • No difference in risk for colorectal cancer

  • Reduced risk of fracture

The WHI recommends that women follow the FDA advice on hormone (estrogen-alone or estrogen-plus-progestin) therapy. It says that hormone therapy should not be taken to prevent heart disease.

These products are approved therapies for relief from moderate to severe hot flashes and symptoms of vaginal dryness. Although hormone therapy may be effective in preventing fractures, it should only be considered for women at high risk of osteoporosis who cannot take other medicines.

The FDA recommends that hormone therapy be used at the lowest doses for the shortest time needed to achieve treatment goals. Postmenopausal women who use or are considering using hormone therapy should discuss the possible benefits and risks to them with their health care providers.

The National Heart, Lung, and Blood Institute offers the following suggestions for women who are deciding whether or not to use hormone therapy:

  • Because the study involved healthy women, only a small number of them had either a negative or positive effect from estrogen plus progestin therapy. The percentages describe what would happen to a whole population—not to an individual woman. In the estrogen plus progestin therapy study the increase risk of breast cancer was 8 additional cases for every 10,000 women over a year. There was a 24% increase overall.

  • The most important thing a woman can do in deciding to continue hormone therapy is discuss the current research with her health care provider and health care team.

  • Women need to be aware that taking a combined progesterone and estrogen regimen or estrogen alone is no longer recommended to prevent heart disease. A woman should discuss other ways of protecting the heart with her health care provider.

  • Women should discuss with their health care providers the value of taking combined progesterone and estrogen therapy or estrogen to prevent osteoporosis. There may be other treatments based on a woman's health profile.

Always consult your health care provider for more information.

What is hormone 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 is called menopausal hormone therapy (MHT). This approach used to be called hormone replacement therapy or HRT. MHT describes several different hormone combinations available in a variety of forms and doses.

How is hormone therapy administered?

According to the American Medical Association, 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 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 treatment, as treatment approaches and dosages can be adjusted.

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Take the PMS Quiz

Premenstrual syndrome (PMS) refers to a range of monthly symptoms that starts 1 to 2 weeks before a woman's menstrual period. Most women have at least some PMS symptoms. Learn more about PMS by taking this quiz.

1. Which group of women is more likely to have PMS?
2. What portion of menstruating women reports at least one symptom of PMS?
3. A more severe form of PMS is also known as:
4. How many different symptoms have been tied to PMS?
5. Symptoms of PMS can be confused with:
6. Which of these hormones is thought to play a role in PMS?
7. What has to occur for the symptoms to be diagnosed as PMS?
8. What lifestyle change will ease PMS symptoms?