Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Breast Cancer Health Center

Font Size

Hormone Therapy May Skew Mammograms

Abnormal Mammograms Found in Some Women Taking Estrogen and Progestin, Study Shows

Combined Hormone Therapy Revisited continued...

Compared with women who did not take the hormones, women taking them had a 4% greater risk of having an abnormal mammogram after one year of hormone use and an 11% greater risk after five years of use.

To put it another way, roughly one in three women who took the hormones (35%) had abnormal mammograms, compared with slightly less than one in four (23%) placebo-treated women.

Breast biopsies were also more common in women taking hormones, with 10% having biopsies compared with 6% of women in the placebo arm of the study.

Biopsies led to a diagnosis of breast cancer in 15% of women taking estrogen and progestin and just under 20% of women who did not take hormones.

The updated WHI findings appear in the Feb. 25 issue of the Archives of Internal Medicine.

"This shouldn't scare anybody away from taking combined hormone therapy if they need it," Chlebowski says. "But women on the fence may decide that the extra risk of having a mammogram that needs follow-up isn't worth it."

The Experts Weigh In

Hormone therapy can make the breasts denser, and denser breasts are harder to image.

But earlier findings by Chlebowski and colleagues suggest that changes in breast density alone do not fully explain the increase in abnormal mammograms seen in women taking combined hormone therapy.

He says that his previous research has not shown an increase in mammograms that require biopsies in women taking estrogen alone.

American Cancer Society Director of Screening Robert Smith, PhD, says the findings add to the evidence that the risks of combined hormone therapy outweigh the benefits for many menopausal women.

"Unless a woman's quality of life is completely compromised (by menopause symptoms), on balance she would be better off avoiding hormones," he tells WebMD.

But North American Menopause Society incoming President Jo Ann Pinkerton, MD, tells WebMD that the breast cancer risk associated with short-term use of combined hormones is quite small for menopausal women.

Clinicians now routinely prescribe lower doses of hormones than were given to the women in the WHI trial in an effort to further reduce the risk.

Today on WebMD

Breast Cancer Overview
From self-exams and biopsies to reconstruction, we’ve got you covered.
Dealing with breast cancer
Get answers to your questions.
woman having mammogram
Experts don’t agree on all fronts, but you can be your own advocate.
woman undergoing breast cancer test
Many women worry. But the truth? Most abnormalities aren’t breast cancer.
Breast Cancer Treatments Improving
Resolved To Quit Smoking
Woman getting mammogram
Screening Tests for Women
ovarian cancer overview slideshow
serious woman
what is your cancer risk
10 Ways to Revitalize Slideshow