A mammogram is an X-ray of the breast. It’s a screening tool used to detect breast cancer. Together with regular clinical exams and monthly breast self-examinations, mammograms are a key element in the early diagnosis of breast cancer.

Even though thinking about getting one might make you uncomfortable, annual mammograms are important after age 40. According to the National Cancer Institute, breast cancer is the second most common cancer for women in the United States, after skin cancer.

In 2021, it’s predicted that there will be about 281,550 new cases of breast cancer in women, according to Breastcancer.org. Learn about how mammograms work, who should get them, and more.

Main uses of mammograms

If your doctor orders a mammogram as a routine test to check for any cancer or changes, it’s known as a screening mammogram. In this type of test, you’ll get several images of your breast taken with the use of a machine.

If you have a lump or any other symptom of breast cancer, your doctor will then order a diagnostic mammogram. If you have breast implants, you’ll probably need a diagnostic mammogram.

Diagnostic mammograms are more extensive than screening mammograms. They typically require more X-rays to get views of the breast from multiple positions. Your radiologist may also magnify any areas of concern.

Some experts, including the American College of Obstetricians and Gynecologists and the National Comprehensive Cancer Network, recommend that women who are age 40 and older should have a mammogram every 1 to 2 years. The American Cancer Society recommends regular screening beginning at age 45.

If you have a personal or family history of breast cancer, your doctor may recommend that you start screenings earlier, have them more often, or use additional diagnostic tools.

Most people feel some discomfort during a mammogram when their breasts are compressed. Your exact experience will vary depending on a few unique factors, such as:

  • breast size
  • breast tenderness related to an expected upcoming period
  • the technician’s skill set

Any pain or discomfort you feel should be short-lived. The procedure takes about 20 minutes, but the parts that lead to pain or discomfort only last for a few seconds at a time.

You’ll need to follow certain guidelines on the day of your mammography appointment. You should avoid applying the following substances, which can show up as white spots on the image:

  • deodorants
  • body powders
  • perfumes
  • ointments or creams on your breasts or underarms

Be sure to tell your radiologist before the exam if you’re pregnant or breastfeeding. In general, you will not be able to receive a screening mammogram at this time, but if necessary, your doctor can order other screening methods, such as an ultrasound.

After undressing from the waist up and taking off any necklaces, a technician will give you a smock or gown that ties in the front. Depending on the testing facility, you may either stand or sit while the images are taken.

Each breast fits onto a flat X-ray plate. A compressor will then push the breast down to flatten the tissue. This provides a clearer picture of the breast. You might have to hold your breath for each picture. You may feel a small amount of pressure or discomfort, but it’s usually very brief.

During the process, your doctor will review the images as they are made. They may order additional images that show different views if something’s unclear or needs further attention. This happens quite frequently and is considered routine.

Digital mammograms

Digital mammograms are sometimes used if they’re available. These are especially helpful if you’re younger than 50 years old. People in this age group typically have denser breasts compared with older adults.

A digital mammogram transforms the X-ray into an electronic picture of the breast that saves onto a computer. Images are immediately visible, so your radiologist doesn’t have to wait for the images.

The computer can also help your doctor see images that might not have been very visible on a regular mammogram.

Yes, mammograms are safe.

As with any type of X-ray, you’re receiving exposure to a very small amount of radiation during mammography. However, the risk from this exposure is extremely low.

If a person is pregnant and absolutely needs a mammogram before their delivery date, they’ll typically wear a lead apron during the procedure.

If you’re over age 40, your health insurance will likely cover the cost of a mammogram. Contact your insurance provider to learn which types of mammograms are covered and whether you’ll need to pay any out-of-pocket costs.

If you don’t have health insurance or your coverage does not include mammograms, you can access free or low-cost mammograms through services like the National Breast and Cervical Cancer Early Detection Program. You can also find discounted mammograms every October in honor of Breast Cancer Awareness Month through the Food and Drug Administration’s website.

If possible, it’s best to get this type of screening in a facility that specializes in mammograms. Those accredited by the American College of Radiology have technicians who are specially trained in mammography. These facilities use equipment that meets specific standards and is inspected regularly.

Consider finding a facility that also does additional testing, such as MRI, ultrasound, or other imaging procedures in case you need further screening.

In terms of annual mammograms, try to use the same facility every year if possible. This makes it easier to compare the results from year to year. If you’re visiting a new facility for the first time and have had prior mammograms, consider bringing the old images with you.

Images from a mammogram can help find calcifications, or calcium deposits, in your breasts. The test can also find cysts — which may come and go normally during some people’s menstrual cycles — and any cancerous or noncancerous lumps.

There’s a national diagnostic system for reading mammograms called the Breast Imaging Reporting and Database System (BI-RADS).

In this system, there are seven categories, ranging from zero to six. Each category describes whether additional images are necessary and whether an area is more likely to have a benign (noncancerous) or cancerous lump.

Each category has its own follow-up plan. Actions on the follow-up plan may include:

  • gathering additional images
  • finding previous mammogram images for comparison
  • continuing regular screenings
  • making an appointment for follow-up in 6 months
  • performing a biopsy

Your doctor will review your results and explain the next steps to you during a follow-up appointment.