Medically Reviewed By William C. Lloyd III, MD, FACS

What is a mammogram?

A mammogram is an X-ray of the breasts. A mammogram starting at age 40 is an important screening test for breast cancer. Used along with other tests, a mammogram can help detect breast cancer at an early stage when it is most curable. It can find some lumps or abnormalities that you or your doctor may not feel with a manual breast exam. A mammogram will create a detailed image of the breast to show the size and shape of a lump or change in the breast. Your doctor may order a diagnostic mammogram after finding a lump, you have other signs and symptoms of a breast condition, or if you have dense breast tissue. A three-dimensional, or 3D mammogram is a newer type of mammogram. A radiologist takes multiple X-rays from different angles and reconstructs them into a 3D view of the breast. Another name for it is breast tomosynthesis.

A normal mammogram result shows no breast lumps or other irregularities in the images. An abnormal result might indicate benign (noncancerous) tumors, cysts, breast cancer (cancerous tumors), calcium deposits, or dense areas of breast tissue. A radiologist will review your mammogram images. compare the findings with previous mammograms when available, and discuss them with your doctor. Your doctor will then discuss the results with you. Together, you will decide what next steps (if any) you need to take based on the mammogram results.

A mammogram is only one method used to screen for breast cancer and other breast abnormalities. Discuss all of your screening options with your doctor to understand which methods should be used and when.

Other procedures that may be performed 

A mammogram alone cannot diagnose cancer. Your doctor will probably recommend further testing if a mammogram finds an abnormality. Other tests include:

  • Breast magnetic resonance imaging (MRI) makes a detailed, high-resolution picture of your breast. A breast MRI provides much more detail than a standard mammogram.

  • Breast biopsy of the lump or abnormal area

  • Breast ultrasound to tell whether a lump is solid or filled with fluid. Radiologists and surgeons also use ultrasound to guide a breast biopsy.

Why is a mammogram performed?

Your doctor may recommend a mammogram to diagnose or screen for diseases and conditions of the breast. A mammogram is used for:

  • Diagnosis of breast irregularities that you or your doctor sees or finds during a breast exam. These include breast lumps, pain, nipple discharge, or changes in breast shape or texture.

  • Follow-up on previous abnormal mammograms to track the progress of any lumps or irregularities

  • Screening for breast cancer in otherwise healthy women with no symptoms. Most women with a normal risk of breast cancer start having screening mammograms at age 40. Discuss the timing and frequency of mammograms with your personal physician.

Your doctor may request a 3D mammogram or breast ultrasound if a standard digital mammogram is not sensitive enough to determine with certainty that any irregularity is a benign (noncancerous) breast condition.

Who performs a mammogram?

A radiologic technologist, supervised by a radiologist, usually performs a mammogram. A radiologic technologist is a medical professional who performs imaging procedures and takes care of patients during the procedures. 

A radiologist or diagnostic radiologist evaluates a mammogram. Radiologists specialize in using radiation and other imaging techniques to diagnose and treat a wide variety of conditions from broken bones and birth defects to cancer. Diagnostic radiologists focus on performing and interpreting imaging tests, such as ultrasounds, X-rays, angiograms, CTs, and MRIs. 

How is a mammogram performed?

Your mammogram will be performed in a hospital or outpatient setting. Mammograms take less than an hour and generally include these steps:

  1. You will undress and remove all jewelry from the waist up and wear your own clothing from the waist down.

  2. You will stand or sit in front of the mammography machine, depending on which type of machine it is. 

  3. The radiologic technologist will place one of your breasts at a time on an X-ray plate. A compressor will flatten your breasts between two plates to spread out the tissue. This helps the machine to get the clearest possible images. A 3D mammogram also involves breast compression, but it is only to hold the breast still. It is not as severe as that experienced with a standard breast X-ray device.

  4. The radiologic technologist will leave the room and take a few pictures of your breast from different angles with the X-ray machine. He or she may ask you to hold your breath during each picture. 

  5. When the pictures are complete, the machine will release your breast from compression.

  6. The radiologic technologist repeats this process with your other breast.

  7. Once the exam is complete, you may get dressed and relax.

  8. You may wait a short period of time while the radiologic technologist or radiologist verifies that the imaging is complete. You will probably go home right after the exam.

Will I feel pain?

Your comfort and relaxation is important to you and your care team. You may feel pressure, pinching, or pain during breast compression in the mammography machine. Take a few long, deep breaths to help yourself relax. Tell your care team if the discomfort or pain does not pass quickly. 

Breasts are often more tender during the week before or during your period. This can make the mammogram more uncomfortable. You doctor will probably recommend that you schedule your mammogram after your period. This is also the best time during your menstrual cycle to obtain the most accurate test results.

What are the risks and potential complications of a mammogram?

Mammograms do not detect all cases of breast cancer. It is very important that you perform regular breast self-exams and see your doctor regularly. This increases the chances of finding breast cancer at the earliest stage possible.

There is also a slightly increased lifetime risk of cancer due to the radiation exposure involved with mammography. Your care team follows strict standards for X-ray techniques and will use the lowest amount of radiation possible to produce the best images. Your doctor will generally not order an X-ray if you are pregnant due to the danger of radiation to an unborn child. It is very important to tell your doctor if there is any chance of pregnancy.

How do I prepare for my mammogram?

You are an important member of your own healthcare team. The steps you take before your procedure can improve your comfort help obtain the most accurate test results.

You can prepare for a mammogram by:

  • Answering all questions about your medical history and medications you take. This includes prescriptions, over-the-counter drugs, herbal treatments, and vitamins. It is a good idea to carry a current list of your medical conditions, medications, and allergies at all times.

  • Avoiding deodorant, lotions, powders, or other substances on your torso and underarms the day of your mammogram. These items can distort the mammography images and may cause an additional test to be necessary.

  • Wear clothing with a separate top and bottom (such as a shirt and pants), so that you can undress from the waist up and keep your own clothing on from the waist down.

  • Telling your doctor and care tea, if you are breastfeeding or there is any possibility of pregnancy

  • Scheduling your mammogram during the week to ten days after your period. Breasts are often more tender during the week before or during your period. This can make the mammogram more uncomfortable. The week after your period is also the best time during your menstrual cycle to obtain the most accurate test results.

Questions to ask your doctor

Having a mammogram can be stressful. It is common for patients to forget some of their questions during a doctor’s office visit. You may also think of other questions after your appointment. Contact your doctor with concerns and questions before your procedure and between appointments.

It is also a good idea to bring a list of questions to your appointments. Questions can include:

  • Why do I need a mammogram? Are there any other options for diagnosing or screening my condition?

  • How long will the procedure take? When can I go home?When and how will I receive the results of my test?

  • What other tests or treatments might I need?

  • When should I follow up with you?

  • When and how should I contact you? Ask for numbers to call during and after regular hours.

What can I expect after my mammogram?

Knowing what to expect after a mammogram can help you get back to your everyday life as soon as possible.

How will I feel after the mammogram?

You should be able to return to all your normal activities immediately after the mammogram. A mammogram may cause you some discomfort during the procedure. Any discomfort should go away quickly. Tell your doctor if you have continuing pain or discomfort after the mammogram. 

When can I go home?

You will probably go home immediately after your mammogram is complete.

When should I call my doctor?

You should keep your follow-up appointments after a mammogram. Contact your doctor if you have any concerns between appointments, such as new changes in your breasts.

Was this helpful?
  1. Mammograms fact sheet.
  2. Mammograms. National Cancer Institute.
  3. Mammography. Radiological Society of North America.
  4. Breast Ultrasound. Radiological Society of North America.
  5. Digital Tomosynthesis.
  6. Tagliafico AS, Calabrese M, Mariscotti G, et al. Adjunct Screening With Tomosynthesis or Ultrasound in Women With Mammography-Negative Dense Breasts: Interim Report of a Prospective Comparative Trial. Journal of Clinical Oncology. 2016;34(16):1882-1888.
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Aug 21
View All Women's Health Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.