Hormone Replacement Therapy: Answers to your questions

For some women, menopausal symptoms can be very uncomfortable, leading to loss of sleep, mood swings, hot flashes and diminished sexual satisfaction. Although symptoms can be very disturbing, they are not considered dangerous or life-threatening. Hormone replacement therapy (estrogen with or without progesterone) has traditionally been prescribed to relieve these symptoms.

Preliminary research had suggested that estrogen therapy could also prevent heart disease and protect against osteoporosis. However, these early studies had limitations in their design. In an effort to provide more definitive answers on hormone replacement therapy (HRT), the National Institutes of Health funded a very large study named the Women’s Health Initiative (WHI)

Over 16,000 postmenopausal women participated in WHI research on the outcomes of combined estrogen and progestin therapy (Prempro®). In May 2002, after 5 years of study, this research was stopped early (the study's original duration was to be 8.5 years). Findings indicated that overall health risks – including increased risk of breast cancer, heart attacks, stroke and blood clots – exceeded benefits from Prempro® usage.

While these results raise important questions about HRT use during menopause, there is no one-size-fits-all answer. The right decision about HRT for each woman is unique to her circumstances, family history, and health profile. Dr. Heidi Nelson, medical director of the Providence Regional Women & Children's Program, urges patients to consider this new WHI information carefully and speak with their physician about whether HRT is right for them.

This FAQ provides answers to questions that many women are asking about HRT.

Q. Do I need to stop my hormone replacement therapy today?

A.No. Although recent studies show an unpredicted increase in risk of heart disease and breast cancer, overall the risk for each individual woman is still low. It is best to discuss your own risks and benefits with your health care provider before deciding whether to continue or start HRT.

Q. What are the risks and benefits of HRT?

A: The Women’s Health Initiative (WHI) study included more than 16,000 women with an intact uterus who received either Prempro® or a placebo (a sugar pill). Prempro® is a combination tablet that contains congugated estrogen (Premarin® 0.625 mg) plus medroxyprogesterone 2.5 mg.

In each year, if 10,000 women were to take a placebo and 10,000 women were to take HRT, the following events would occur:


(sugar pill)


Risks & Benefits

Heart Attacks

30 cases

37 cases

7 more cases

Breast Cancer

30 cases

38 cases

8 more cases


20 cases

29 cases

9 more cases

Blood Clots

16 cases

34 cases

18 more cases

Hip Fractures

15 cases

10 cases

5 less cases

Colon Cancer

16 cases

10 cases

6 less cases

The five-year study found no difference in the number of deaths between women taking HRT and placebo.

Q: I have had a hysterectomy. How do these studies apply to me?

A:The recently published studies did not include women who had had a hysterectomy and are now only taking estrogen. The Women's Health Initiative (WHI) study did include a group of women who had undergone hysterectomies, but this part of the study is still underway. The results of this part of the study are not expected to be available until 2005.

Some researchers have theorized that it is the progesterone, not the estrogen that increases a woman’s risk of heart disease and possibly other problems. If this is true, then women taking estrogen following a hysterectomy may not be at increased risk. However, until the results of this part of the WHI study are published, this theory remains controversial.

Q: I started HRT to prevent heart disease. Should I continue?

A: Physicians and researchers have been surprised to find that HRT did not protect against heart disease in recent placebo-controlled studies. There is now data available that suggests you should not begin taking HRT if you currently have heart disease.

In addition, research does not support the theory that HRT prevents heart disease. Although there may be other reasons to begin HRT (such as to treat symptoms of menopause), prevention of heart disease alone is no longer a reason for women to take HRT.

Q: I heard that HRT protects my bones. Is this still true?

A: HRT has been shown to help prevent bone loss and prevent hip fractures. This is primarily true if you started HRT when your menopausal symptoms first began. If you are concerned about osteoporosis, discuss all of your options with your health care provider before deciding if HRT is a good choice for you.

All women should consider regular weight-bearing exercise and take adequate calcium and vitamin D intake every day to prevent osteoporosis.

Q: Does HRT really increase my risk of breast cancer?

A: There is some evidence that your risk of breast cancer can increase slightly with HRT. The Women's Health Inititiave (WHI) studies showed that if 10,000 postmenopausal women with an intact uterus took estrogen plus progestin for one year, eight more would develop breast cancer compared to women not taking HRT. 

Whether or not you are taking HRT, you should keep up with your regular breast self-examinations and mammograms.

Q: What about blood clots in my veins?

A: Taking HRT does increase your risk of developing a blood clot in your lower leg veins that can sometimes travel to your lungs. This increased risk does not go away with time. Risk of blood clots is typically higher for women who smoke cigarettes or who remain in one position for long periods of time, such as during airplane flights or car trips longer than four hours.

Q: Are there other types of estrogen that I should consider taking?  What about “natural” estrogen products?

A: The most common estrogen taken in the United States is Premarin®, otherwise known as a congugated estrogen. Prempro® (which combines Premarin® with medroxyprogesterone) was the product studied in the Women's Health Initiative (WHI).

There are other prescription hormones available, as well as over-the-counter products that have, or claim to have, estrogen properties. Unfortunately there is little information available about the risks and the benefits of these other types of estrogens. It is tempting to feel “safe” by taking a hormone other than the medications studied in the WHI. However, there is no information to show that these products are as effective or safer than Prempro®.

Q: Would a lower dose of estrogen be better for me?

A: Since a lower dose of estrogen was not studied, it is difficult to know exactly how taking a lower dose would affect the risks and benefits of taking estrogen. Certainly if you are taking estrogen to prevent menopausal symptoms, it is prudent to take the lowest dose that keeps your symptoms under control. Whether taking lower doses of estrogen provide the same bone protection is uncertain. Discuss the option of lowering your estrogen dosage with your health care provider.