Dense breast tissue: All you need to know



Last updated:

By Rachel Nall, RN, BSN, CCRN

The breasts are made up of three main components: lobules, ducts, and connective tissue that can be both fatty and fibrous.

Some women have more fibrous tissue in their breasts than they do fatty tissue. When a woman has a high proportion of fibrous tissue, a doctor may diagnose her with dense breasts.

It is important that women are aware of the density of their breasts because denser breasts can make cancerous lesions more difficult for doctors to identify.

Contents of this article:

  • Having dense breasts is not uncommon.
  • Doctors will diagnose dense breast tissue using an imaging scan known as a mammogram.
  • Sometimes, medications can affect a woman’s breast density.
  • As a general rule, a woman’s breasts will become less dense over time.

What is dense breast tissue?

breast, Dense breast tissue: All you need to know
Mammogram showing dense breasts (left) and fatty breasts (right). Image credit: Dr. Kathy Cho, National Institutes of Health, 1994

Breast density is measured by the amount of fatty tissue in the breasts. The more fatty tissue, the less dense the breasts are.

According to some statistics, an estimated 40-50 percent of women aged 40-74 have dense breasts.

Women with dense breasts are more likely to have false-negative mammograms than women who do not have dense breasts, according to the National Cancer Institute. Recent research studies have also linked dense breasts to an increased risk of having breast cancer in both breasts.

While having dense breasts in no way guarantees a woman will get breast cancer, it is known to be a contributory factor and doctors are trying to define its relationship to breast cancer further.

Symptoms of dense breasts?

A common misconception about dense breasts is that they are firm or large. However, a woman with firm breasts does not necessarily have dense breasts. The density of a woman’s breasts can change over time. For example, as a woman ages, hormonal changes may cause more fatty tissue to develop in her breast.

What are the risk factors for dense breast tissue?

breast, Dense breast tissue: All you need to know
Risk factors for dense breast tissue may include younger women and a family history of dense breast.

There are several risk facts including:

  • Age: The younger a woman is, the denser her breasts tend to be. Older women typically have less dense breasts.
  • Medication: Women who take hormone replacement therapy after menopause may see an increase in their breast density.