Aprobado por la Junta Editorial de Cancer.Net, 09/2021

A mammogram is an X-ray that checks for cancer in breast tissue. The technique used to do these X-rays is called mammography. The images may show a small tumor that cannot be felt during an examination or other breast changes.

What are the different types of mammograms?

A mammogram can be done as a routine check-up test or to find the cause of symptoms you are experiencing.

Screening mammogram. This type of mammogram is a routine test. You may have it every year, every other year, or at different times depending on what your doctor recommends.

Screening mammograms check for breast cancer in people who do not have symptoms. The goal is to catch any cancer early, when it is usually easier to treat.

Health organizations have different guidelines for how often people need screening mammograms. Learn about current breast cancer screening guidelines and how to make sense of screening recommendations.

Diagnostic mammogram. This type of mammogram is done to learn more about a specific symptom or answer a question. You may need a diagnostic mammogram if:

  • Your screening mammogram shows changes that the doctor wants to know more about

  • You feel a lump in your breast or chest

  • You have other symptoms

A diagnostic mammogram usually takes more pictures of the breast than a screening mammogram.

Who does my mammogram?

A health care team member called a mammographer does the test. They have special training in mammogram technology and in working with you to get the best possible images.

A doctor called a radiologist looks at the images from your mammogram and interprets what they show. You usually receive a written report or letter with your results.

How can I prepare for a mammogram?

When you schedule your mammogram, the hospital or office staff will tell you how to prepare. Here are some things to keep in mind.

When to schedule your mammogram. Consider scheduling the test during the 2 weeks after your period ends. Your breasts will be the least tender at this time of month. If you are concerned about pain during the mammogram, you can take an over-the-counter pain medication on the test day.

What your health care team needs to know before your mammogram. Make sure to tell your health care team about any symptoms you are experiencing in your breast or chest. You should also tell them if:

  • You are pregnant or breastfeeding. While it is generally considered safe to get a mammogram during pregnancy, pregnancy and breastfeeding can make it more difficult for a radiologist to read a mammogram. Depending on the reason for your mammogram, your health care team may recommend postponing this test.

  • You have just received a COVID-19 vaccine. Temporary swelling in the arm that got the shot may mean it is better to postpone this test for a few weeks.

  • You have breast implants, previous surgery to your breasts or chest, and any areas of concern. They may ask you about this information the day of the scan.

All of this information will help the mammographer do the best mammogram possible. It also helps the radiologist who is looking at your mammogram and interpreting the pictures. For example, if you had breast surgery in the past, the mammographer may tape small markers to your skin in that area. This shows the radiologist where the cancer or other problem was.

If you have had a mammogram at another facility before, ask the mammographer if they have access to your records. The radiologist can compare your new images with the older ones.

Insurance and cost. In the United States, the Affordable Care Act requires private insurance companies to pay for regular screening mammograms. Starting at age 40, you can be screened for free every 1 to 2 years. Medicare also pays for a screening mammogram every year, starting at age 40. 3D mammograms (also known as tomosynthesis) are not always paid for, so you should call you insurance company to find out if this type of screening mammogram is covered before having the test.

Diagnostic mammograms are usually covered by your insurance provider. But you should call before the test and talk with them to avoid having any unexpected costs.

What to eat. You can usually eat or drink normally before the test. You may want to avoid caffeine before your mammogram. Caffeine can make your breasts more tender. If you are worried about pain or discomfort during the mammogram, you can take an over-the-counter pain medication 1 hour before your appointment.

What to wear. You will need to remove your clothing from the waist up during your mammogram. You may want to wear a top and bra that are easy to remove. During the exam, you will wear a hospital gown that can open in the front. You may want to leave necklaces at home since you will need to remove neck jewelry before the test. Ask your provider about other types of jewelry if you have questions.

There are some things you should avoid putting on your body before a mammogram:

  • Deodorant

  • Antiperspirant

  • Body powder

  • Lotion

  • Perfume, body spray, or cologne

  • Makeup applied below the neck

These products leave deposits on your skin. This can create spots on the X-ray images, making them more difficult to read. They can cause problems even if the product was not applied directly to your breast.

If you have any questions about how to prepare for your mammogram, ask your health care team. They will let you know if there is anything you need to do before the test or bring with you to your appointment.

What happens during a mammogram?

The actual mammogram takes 10 to 15 minutes, but your appointment can take up to an hour. This includes changing clothes, having the examination, and your mammographer making sure the images are clear enough for the radiologist to look at.

During the mammogram, you will stand in front of the mammography machine. This is a tall machine with two flat plates and a tube on top. The mammographer will adjust the machine to your height and then rest your breast on the bottom plate. The top plate, called the compression plate, will lower onto your breast. The mammographer may ask you to take a deep breath before doing this.

When the breast is flattened between the plates, the machine will take the X-rays from the tube above the breast. This is uncomfortable, but does not last long. Some people do experience pain during a mammogram, but if you feel severe pain or if your skin is pinched, tell the mammographer.

For a screening mammogram, you will need several pictures of each breast. A diagnostic mammogram may need more. The mammographer might have you change positions a few times. After you are done, they make sure the pictures are clear. They may retake any pictures that are not clear. When the mammogram is finished, you can go back to your usual activities right away.

Today, most breast imaging centers use digital technology instead of film. The pictures are easier to store and share, and they can be ready sooner. The images are also sharper, which can make it easier to see small changes.

Even with digital mammograms, you will not get your test results right away. This is because the radiologist needs to read the results carefully. You should receive the results of a screening mammogram within 2 to 4 weeks. Diagnostic mammogram results are usually given sooner. Ask the mammographer when you can expect your results.

Why does my breast need to be flat during a mammogram?

The type of X-ray used in a mammogram is less powerful than other kinds of X-rays. To make it easier to see abnormalities, the breast tissue is flattened out. It also keeps the breast tissue from moving around, which would produce a blurry picture.

Should I get a 3-D mammogram?

Many breast imaging centers offer 3-dimensional (3-D) mammograms. This is also called breast tomosynthesis.

During a 3-D mammogram, the breast is positioned and flattened in the same way. But 3-D imaging takes a few seconds longer. The X-ray tube moves in an arc, taking pictures from many angles. A computer creates images that show multiple sections of the breast.

Some studies show that 3-D imaging means less need to come back for another mammogram if changes are found.

Each type of mammography has benefits and risks. Ask your health care team which type is right for you.

Why did I get called back for another mammogram?

Sometimes, your doctor may need you to come back to get additional pictures of your breast. While you may be worried when you get this call, it may help to know that it is common. The most common reasons for getting a call back for another mammogram are either dense breast tissue that makes it difficult to see any problems in the breast or an area of concern. Most of the time, an area of concern on a mammogram is not cancer.

What happens if my mammogram result is abnormal?

If the radiologist is concerned your mammogram results show a growth that could be cancer, the next step is additional testing. These tests will find out if the growth is benign or cancerous. A benign tumor means that the tumor can grow but it will not spread. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body.

Your doctor may decide to do additional imaging tests, like an ultrasound or a breast MRI. But the only way to confirm a breast cancer diagnosis is through a biopsy. There are several different kinds of biopsies used to diagnose breast cancer. Learn more about the tests used in making a diagnosis of breast cancer.

Questions to ask your health care team

Before having your mammogram, consider asking:

  • Why are you recommending this test for me?

  • Where will my mammogram be done?

  • Who will do the mammogram?

  • Can I choose a female mammographer if I am more comfortable with that?

  • Does the center do a lot of mammograms?

  • What are the possible risks of a mammogram?

  • How accurate are mammograms at finding cancer?

  • When will I get the results, and how?

  • Who will explain the results to me?

  • What other tests will I need if the mammogram is not clear or shows signs of cancer?

Related Resources

Breast MRI

Guide to Breast Cancer

Cancer Screening

Mammograms and Older Women: Is It Ever Safe to Stop?

More Information

MedlinePlus: Mammography

National Cancer Institute: Mammograms

RadiologyInfo: Mammography