Are My Breasts Normal?

Normal breast anatomy 

Breasts are primarily made of fat and breast tissue, which consists of a series of ducts and glands designed to produce and move milk to the nipple for breast feeding. Fibrous tissue, also known as connective tissue, supports the breast and holds everything in place. Some breasts have more fat than tissue, some breasts have more tissue than fat.

Any combination of tissue and fat is normal. If you have more tissue than fat, your breasts are considered dense.

Throughout a woman’s life, her breasts will go through a series of changes as they mature. Generally, before menopause, the breasts have more breast tissue than fat (higher breast density) and after menopause the breasts have more fat than breast tissue (lower breast density).

This loss of breast tissue means that a woman’s breast density generally decreases during and after menopause, although some women into their 70s continue to have dense breast tissue.   

Breast density decreases as women age.19 These are the statistics for density by age category:  
74% of women between age 40-49 years
57% of women in their 50s
44% of women in their 60s
36% of women in their 70s

Breasts that have more tissue than fat are harder to read on a mammogram and are described as dense.  If you have dense breasts, ask your doctor if additional testing would be right for you.

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Dense Breasts

What is breast density?

Each woman’s breasts are unique and have varying amounts of fat and breast tissue.  Breast density is measured as the total percentage of tissue in the breast:

  • High breast density means there is more breast tissue compared to fat
  • Low breast density means there is a more fat compared to breast tissue

Having high breast density is perfectly normal.  Breast density affects what your breasts look like on a mammogram.  Dense breast tissue has the potential to hide cancer on a mammogram and is a risk factor that may increase a woman’s chance of developing breast cancer by 4-6 times2 as compared to women with fatty breast tissue.


Learn more

>> Download a GE Healthcare breast density fact sheet.
>> Download a GE ABUS patient pamphlet.


You should ask your doctor about your breast density.  Your doctor can assess your breast density from your mammogram.  If you have dense breasts, ask your doctor how this impacts your personal risk of developing breast cancer and if additional testing would be right for you.

Breast density masks the appearance of cancer  

Breast density plays a significant role in the ability of mammograms to detect early breast cancer.  Fat looks dark on a mammogram, but both dense breast tissue and cancer appear white. Therefore, on a mammogram, a cancer can easily hide in a background of dense breast tissue since they both appear white.

Some radiologists describe this as trying to locate a specific cloud in a cloudy sky.   According to research, 35 percent of breast cancer goes undetected by mammography alone in women with dense breasts, as density masks the appearance of tumors.

This is important because even though mammograms remain the gold standard tool for screening, they do not work equally well in all women. As a result, women with dense breast tissue may need additional tests.  Studies have shown that certain supplemental imaging exams, such as breast ultrasound, improve the sensitivity of detecting cancer when used together with mammography. On ultrasound, tissue appears black and cancer appears white, helping make it more visible to the radiologist.

An emerging technology for screening women with dense breasts is automated breast ultrasound (ABUS).

>> View a video about why dense tissue may hide cancer. (Please note: by clicking this link you are leaving this GE Healthcare website.)

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Breast Cancer

Invasive versus non-invasive breast cancer

While breast cancer is referred to as one disease, there are different forms of breast cancer, including invasive and non-invasive types.

A breast tumor sometimes grows slowly, and may have been growing for up to 10 years before it is large enough to be felt during a breast exam. Other types of breast cancers are very aggressive and can grow much faster.6

When abnormal cells grow inside the milk ducts, but have not spread to other areas, the condition is called ductal carcinoma in situ (DCIS). DCIS is a non-invasive breast cancer that can develop into invasive cancer. About 1 in 5 new breast cancer cases will be DCIS7. The earlier breast cancer is caught, the better chance a person has of surviving five years after being diagnosed. For breast cancer, 60.8% are diagnosed at the local stage. The 5-year survival for localized breast cancer is 98.5%.8

Invasive breast cancer occurs when abnormal cells from inside the milk ducts or glands break out into nearby breast tissue. Cancer cells can travel from the breast to other parts of the body through the blood stream or the lymphatic system. Lymph nodes are small, bean-shaped organs that are part of the bodies’ immune system and are important in fighting infections. The lymph nodes in the underarm area (axillary lymph nodes) are the first place breast cancer is likely to spread, or metastasize, to other parts of the body.


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Genetic breast cancer risk factors

Genetic mutations – Inherited genetic mutations (abnormalities) account for only an estimated 5-10 percent9 of all breast cancers diagnosed in the US and are considered rare in the general population.  

  • BRCA1 and BRCA2: The most common inherited mutations are the BRCA1 and BRCA2 genes.10 A woman with a mutated copy inherited from a parent has a higher risk of developing breast cancer during her lifetime.  Ask your doctor if genetic testing would be right for you.

Personal history of breast disease – Women who have had breast cancer are at increased risk of developing a new cancer (this is different than return of a prior cancer).  

Dense breast tissue – Women with dense breasts may have a 4-6 times greater chance of developing  breast cancer than women with fatty breast tissue. Breast density is a way to describe the composition of a woman's breasts. Some women have more fat than breast tissue while others have more breast tissue than fat. When there is more breast tissue than fat, the breast is considered dense. It is estimated that more than 40 percent of women in the U.S. have dense breast tissue.

>> Download an infographic about breast cancer awareness and risks.


<< Back to Know Your Risk: Risk Factors

True or False: Wearing a bra increases your risk of breast cancer.

True or False: Having dense breasts increases your risk of breast cancer.

True or False: Having breast implants increases your risk of breast cancer.

True or False: Being overweight increases your risk of breast cancer.

True or False: Breastfeeding may lower your risk of breast cancer.

True or False: Caffeine intake increases your risk of breast cancer.

True or False: Wearing antiperspirant increases your risk of breast cancer.

Ask Your Doctor

Questions to ask your doctor

Knowledge is power.  The more you know about your breast health, the better you are able to have knowledgeable conversations with your doctors and to make individualized healthcare decisions. If you have been informed you have high breast density, here are some questions that you may want to ask your doctor:

  • How often should I get a mammogram?
  • Do I have dense breasts?
  • What does having dense breasts mean?
  • How does having dense breasts impact my risk of getting cancer?
  • Is there a way to reduce my risk of getting breast cancer?
  • Are there tests other than a mammogram for women with dense breasts?
  • Will I always have dense breasts?


Automated Breast Ultrasound (ABUS)

Demonstrating up to 55 percent13 improvement in invasive cancer detection over mammography* in women with dense breasts, ABUS technology from GE Healthcare is the only ultrasound device approved by the U.S. FDA for screening women with dense breasts. This system was developed specifically for dense breast imaging to help find cancer which may be missed by mammography.  

Multiple clinical research studies14 demonstrate that radiologists can detect more cancers in women with dense breasts at an earlier, more treatable stage when using ABUS as an adjunctive screening tool with mammography.

Unlike mammography, an ABUS exam does not involve strong compression of the breast.  Women lay down on an exam table and a layer of lotion is applied to the breast. Then a scanner is firmly positioned on the breast to create the images. The exam takes approximately 15 minutes and creates clear 3D ultrasound images which will be reviewed by the physician along with the woman’s mammogram.

>> Download an ABUS exam pamphlet.

View an ABUS Exam Demonstration:

>>View a video about how ABUS helps find cancer in dense tissue as a supplement to mammography. (Please note: by clicking this link you are leaving this GE Healthcare website.)


2. Boyd, et al, NEJM Jan 2007.
6. Journal of Women’s Imaging, 2003:5:11–19, "Breast cancer tumor growth estimated through mammography data." Published in the May 8, 2008, Breast Cancer Research (Vol. 10, Issue 3). First author: Harald Weedon-Fekjær, Department of Etiological Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Montebello, N-0310 Oslo, Norway.
7. American Cancer Society. Cancer Facts and Figures 2014. Atlanta, GA: American Cancer Society, 2014. Dillon DA, Guidi AJ, Schnitt SJ. Chapter 28: Pathology of Invasive Breast Cancer, in Harris JR, Lippman ME, Morrow M, Osborne CK. Diseases of the Breast, 4th edition, Lippincott Williams & Wilkins, 2010.
9. Schwartz GF, Hughes KS, Lynch HT, et al. Proceedings of the international consensus conference on breast cancer risk, genetics, & risk management, April, 2007. Cancer. Nov 15 2008;113(10):2627-37.
10. Campeau PM, Foulkes WD, Tischkowitz MD. Hereditary breast cancer: New genetic developments, new therapeutic avenues. Human Genetics 2008; 124(1):31–42. Walsh T, Casadei S, Coats KH, et al. Spectrum of mutations in BRCA1, BRCA2, CHEK2, and TP53 in families at high risk of breast cancer. JAMA 2006; 295(12):1379–1388.
13. Brem RF, Tabár L, Assessing Improvement in Detection of Breast Cancer with Three-dimensional Automated Breast US in Women with Dense Breast Tissue: The SomoInsight Study. Radiology. 2015 Mar; 274(3): 663-73.
14. Study results compiled from USI, 20082002, NCT00816530 data.
19. Checka et al. The relationship of mammographic density and age: implications for breast cancer. AJR Am J Roentgenol. 2012 Mar;198(3):W292-5.

*Increase in sensitivity is associated with a decrease in specificity.

Find a Facility

Early detection of breast cancer enables treatment to be started earlier in the course of the disease, possibly before it has spread.

Advocate for your health and schedule a breast exam today.

Use the GE Healthcare ABUS Locator application to find a facility in your area.