Half of all women have dense breasts, and it's important to know if you are one of them. However, you likely don't know if you have dense breasts until you have a mammogram. That's why health providers encourage women to get regular breast cancer screenings beginning at age 40.

Here's some more information for women with dense breasts and the importance of screening for all women.

What does it mean to have dense breasts?

Breasts contain three types of tissue: glandular tissue, fibrous connective tissue and fatty breast tissue. Breast density describes how much of these tissues are seem on a mammogram. Dense breast tissue has higher amounts of glandular and fibrous connective tissues and lower amounts of fatty breast tissue.

What causes some women to have dense breast tissue?

Dense breast tissue is typically something that's passed down from a parent (inherited). Although other factors can lead to dense breasts. People who are younger, who take menopausal hormone therapy, are pregnant or breastfeeding, and have a low body mass index (BMI) are more likely to have dense breasts.

Why is it important to know if you have dense breasts?

There are two reasons:

  1. It makes it harder to detect a breast cancer.
  2. Women with dense breast tissue are at slightly elevated risk for developing a breast cancer.

Women with dense breasts might need additional testing – above and beyond a mammogram – to help detect early breast cancer.

How do you know if you have dense breasts?

Dense breast tissue cannot be felt during a self-exam or by a provider during a clinical breast exam. You won't know if you have dense breasts until you have a mammogram. If your results indicate that you do, talk to your doctor about getting additional tests, such as an ultrasound or MRI. These tests are more effective at detecting cancer in dense breast tissue.

Read more about breast density and your mammogram report

Does having dense breasts make it more difficult to detect breast cancer?

Dense breast tissue can make it more challenging to read a mammogram. That's because dense breast tissue and some abnormal breast changes both appear as white in the mammogram. This makes it more likely that the cancer will be missed. For this reason, it's recommended that women with dense breasts get more testing, such as an ultrasound or MRI.

Are women with dense breasts more likely to have a more advanced stage of breast cancer or die?

Dense breast tissue makes it more difficult to detect cancer, which means the cancer could continue to advance despite regular mammograms. That's why it's important to get additional follow-up testing if you have dense breasts.

However, breast cancer patients who have dense breasts are not more likely to die from cancer as compared those with fatty breasts, according to research.

When should women begin regular screenings for breast cancer?

It's recommended that every woman, regardless of their breast density or risk, have a mammogram each year starting at age 40. If you have a family member who has or had breast cancer, you many need to start screening earlier than 40. Talk to your primary care provider about when you should begin breast cancer screening.

Learn more about breast cancer screening guidelines

Read why it's so important to get regular breast cancer screenings (UC Davis Health)

Why should women begin getting screened in their 40s?

Breast cancer can now be detected when it's very tiny, allowing women to begin treatment right away. This means that women don't have to become sick from the breast cancer, giving them the ability to live a healthy life.

Read more from UC Davis Health: Why women should start getting mammograms at age 40

How can I schedule a mammogram at UC Davis Health?

Talk to your doctor about whether you're at average or increased risk for breast cancer. To schedule a mammogram, contact the Breast Imaging Division at 916-734-0655 or make an appointment on MyUCDavisHealth.

The UC Davis Health Breast Imaging Division is an American College of Radiology accredited Breast Imaging Center of Excellence. We offer a full range of breast imaging services with state-of-the-art equipment. We use a variety of biopsy techniques including digital mammography, tomosynthesis, ultrasound, and MRI. Each of our breast imaging exams is read by specialists.

Medically reviewed by Elizabeth Morris, M.D., chair of the Department of Radiology at UC Davis Comprehensive Cancer Center.