The facts about breast density

Are you dense?

Dense breasts are normal; up to 40% of American women have them. It simply means that a woman has more fibrous, glandular tissue in her breasts than fatty tissue. Younger women typically have denser breast tissue. Older women, especially post-menopausal women, have less dense breast tissue. But if a woman takes postmenopausal hormones, her breasts may remain dense.

Breast density is measured during your annual screening mammogram

All mammography reports from Radiology Associates of Hartford contain a classification of breast density based on the Breast Imaging Reporting and Data System (BI-RADS) breast composition categories:

Breast Density

Category 1: Predominantly fat
Category 2: Scattered fibroglandular densities
Category 3: Heterogeneously dense
Category 4: Extremely dense

Why is breast density important?

While the reasons are not yet fully understood, women with denser breasts are at an increased risk for breast cancer. In addition, clinical studies have shown that women with dense breasts can benefit from a supplemental form of screening in addition to mammography.

Supplemental screening

For women classified as BI-RADS 3 (heterogeneously dense) and BI-RADS 4 (extremely dense). Supplemental screenings can include breast MRI and ultrasound.

Breast MRI is generally recommended for women who are determined to be at high risk for breast cancer (e.g. another family member was diagnosed with the disease). For women at low to moderate risk, we offer supplemental screenings with ultrasound.

Why haven’t I heard of breast density before?

The issue of breast density has only recently emerged into the national spotlight, and the majority of clinical research on the subject is less than ten years old. Seventeen states now have breast density notification laws, and that number is growing.

The clinical evidence is clear, and this is not a medical “fad.” Breast density is not only a risk factor for breast cancer, but it can also impact a woman’s ability to achieve early detection using traditional methods. It is widely agreed that early detection is the key to surviving breast cancer, so any issue that can impact a woman’s confidence in her healthcare strategy must be considered.

Learn the facts for yourself. Talk to your doctor. If you need more information, we are here to help or you can visit the following:


A Leading National Resource for Women with Dense Breasts

American Cancer Society – “Breast Density and Your Breast Mammogram Report”

National Cancer Institute – “What is the Breast Imaging Reporting and Database System (BI-RADS®)?”

Komen – “Facts for Life: Breast Density”