A mammogram is an x-ray of your breasts. X-rays use high energy rays to take pictures of the inside of your body.

People have mammograms:

  • to check for cancer if you have breast symptoms - this is called a diagnostic mammogram
  • as part of the breast cancer screening programme

You might have a mammogram if you have:

  • a new lump or thickening in your breast or armpit
  • a change in size, shape or feel of your breast
  • skin changes in the breast such as puckering, dimpling, a rash or redness of the skin
  • fluid leaking from the nipple in a woman who isn’t pregnant or breast feeding
  • changes in the position of the nipple

You may have this test alongside other tests, such as a breast examination and breast ultrasound in a one-stop clinic. You might also have a biopsy Open a glossary item in this clinic.

Having a breast examination, a scan or mammogram, and a biopsy is known as a triple assessment.  

The mammogram itself only takes a few minutes. But you are usually in the clinic longer, especially if you have other tests.  

Diagram showing a woman having a mammogram

Preparing for a mammogram

There are no special preparations for a mammogram. You can eat and drink normally beforehand.

Avoid using talcum powder or deodorant on the day of your test as this may affect the mammogram. 

Tell the mammographer if you have breast implants. You may need extra x-rays taken. The mammographer is very experienced in doing mammograms with women with breast implants.

What happens

You have a mammogram as an outpatient. This might be in the x-ray department or a specialist breast clinic. 

You take off your clothes from the waist upwards. You might put on a hospital gown.

You stand close to the x-ray machine. The radiographer positions one breast at a time between 2 flat plates on the machine. The plates press your breast firmly between them for a few moments. You will feel a little pressure and It is likely to be uncomfortable. Some women find it painful, but It is over quickly.

Sometimes you may have more than 2 x-rays so the doctor can see different views of the breast.

3D mammograms

This is a detailed type of mammogram that is available in some hospitals. It takes more x-rays than a standard mammogram. A computer uses these to create a 3-dimensional (3D) image of the breast.

After your mammogram

You can get dressed straight after the mammogram. You might have some tenderness in your breast for up to a few hours.

Specialists called radiologists look at the mammogram pictures. They check for any abnormal areas.

If everything looks normal you might not need any further tests.

If an abnormal area shows on the scan you might need to have more tests. These may include a breast ultrasound scan or taking a sample of cells from the breast (a biopsy).

In a one-stop clinic, you have these tests during the same visit.

Getting your results

You might get the results on the same day. If you had a breast biopsy you might need to wait for a week or so. 

Waiting for test results can be a very worrying time. You might have contact details for a specialist nurse who you can contact for information if you need to. It can also help to talk to a close friend or relative about how you feel.

You can also contact the Cancer Research UK nurses on freephone 0808 800 4040 for information and support. The lines are open from 9am to 5pm, Monday to Friday.

Do contact the staff at the clinic if you haven’t heard anything after a couple of weeks.

Possible Risks

A mammogram is a very safe test, but with any tests, there are possible risks.

Exposure to radiation 

Each mammogram exposes a woman to small amounts of radiation from the x-rays. But the amount of radiation is very small.

X-rays can very rarely cause cancer. Having mammograms every 3 years for 20 years very slightly increases the chance of getting cancer over a woman’s lifetime.


It is very important to tell the mammographer if you think you may be pregnant, as the x-rays could affect your developing baby.

  • Early and locally advanced breast cancer: diagnosis and treatment
    National Institute for Health and Care Excellence (NICE) June 2018

  • Guidance on screening and symptomatic breast imaging (Fourth edition)
    The Royal College of Radiologists
    Clinical Radiology, 2019

  • Independent review of National cancer screening programmes in England, May 2019

    Professor Sir Mike Richards

    NHS England

Last reviewed: 
04 Sep 2020
Next review due: 
04 Sep 2020