Dense breasts are normal and are not caused by illness. All breasts are made of fat, and milk ducts/milk glands held together by fibrous tissue. The glands and fibrous tissue (or “fibroglandular” tissue) are referred to as “dense tissue”.

Each woman’s breasts are different and contain their own mix of fatty and dense tissue. Some women have breasts made of mostly fatty tissue. Some women have breasts with a lot of dense tissue. The more glands and fibrous tissue that a woman has, the “denser” her breast tissue is.

How can I tell if I have dense breasts?

The radiologist (the doctor who looks at your mammogram) can tell how dense your breasts are by how they look on your mammogram. You cannot tell if you have dense breasts by the way your breasts look or feel.

See Patient Education Video, “What is Breast Density?”

Learn More:

• 5 Facts Every Woman Should Know
• Video Series: Let’s Talk About Dense Breasts
• Patient Risk Checklist (print)
• Patient Questions and Answers

Dense breasts are normal and common and can change over time. Younger women tend to
have denser breasts. Breasts tend to become less dense around menopause when estrogen
(a hormone) levels drop.

Why do dense breasts matter?
Dense breasts matter because dense tissue can hide cancer on a mammogram. Dense breasts also increase the risk of developing breast cancer. If you have dense breasts, you may need another test in addition to your mammogram to find cancer (if present).

For more information, see “Dense Breasts: 5 Facts You Should Know”

Learn More:

• 5 Facts Every Woman Should Know
• Video Series: Let’s Talk About Dense Breasts
• Patient Risk Checklist (print)
• Patient Questions and Answers

Dense breasts are normal and common. Though normal, dense breasts do increase the risk of developing breast cancer and of having a cancer missed on a mammogram.

Many women have dense breasts. Density tends to decrease as a woman gets older.

Talk to your health care provider about whether you should have additional tests after your mammogram. Click here for 5 Facts Every Woman Should Know.

Learn More:

• 5 Facts Every Woman Should Know
• Video Series: Let’s Talk About Dense Breasts
• Patient Risk Checklist (print)
• Patient Questions and Answers

In the U.S.A. the FDA now requires that after a mammogram, all patients be told whether their breasts are “dense” or “not dense.”  Click here to see what you must be told about breast density after your mammogram. If you would like to also learn which specific density category your breasts are (heterogeneously dense or extremely dense), you can: (1) ask the place where you had your mammogram, or (2) ask your referring health care provider (that information is included in the report sent to them).

In Europe, the facility that does your mammogram may either have this information or allow you to request it. Density Request forms are available for the UK here.

Learn More:

• 5 Facts Every Woman Should Know
• Video Series: Let’s Talk About Dense Breasts
• Patient Risk Checklist (print)
• Patient Questions and Answers

In the U.S.A., the radiologist (the doctor who looks at your mammogram) will send a report to your health care provider after your mammogram. Your breast density category (fatty, scattered density, heterogeneously dense or extremely dense) is in that report. Your density category may also be in the letter you receive after your mammogram.

In Europe, the facility that does your mammogram may either have this information or allow you to request it. Density Request forms are available for the UK – England/Wales; Scotland; Northern Ireland; Republic of Ireland here.

Learn More:

• 5 Facts Every Woman Should Know
• Video Series: Let’s Talk About Dense Breasts
• Patient Risk Checklist (print)
• Patient Questions and Answers

Maybe not.

• Breasts tend to become less dense with age and menopause (see Figure below), but not always.
• Breasts become more dense (denser) during pregnancy and breast feeding. This is because the glands that make milk grow and the glands themselves are part of dense breast tissue. Breast density returns to what it was before pregnancy about 2-3 months after you stop breast feeding.
• If you lose a lot of weight, your breasts may appear denser on a mammogram because there is less fat, but the amount of dense tissue stays the same.

Breasts Can Become Less Dense with Age and Menopause

Left Image: A screening mammogram image of a premenopausal woman (age 49) shows heterogeneously dense breast tissue (Category C).

Right Image: A screening mammogram image of the same woman, now postmenopausal (age 52). Her breasts are less dense and now show scattered fibroglandular density (Category B).

Learn More:

• 5 Facts Every Woman Should Know
• Video Series: Let’s Talk About Dense Breasts
• Patient Risk Checklist (print)
• Patient Questions and Answers