A mammogram is an X-ray of the breasts (mammary glands) used to screen for breast problems, such as lumps or small tumors that can be seen before they can be felt. Mammograms do not prevent breast cancer or reduce a woman's risk of developing cancer but they can detect cancer early, when it is more easily treated.

While experts differ in their recommendations about when to start and how often women should have mammograms, the most common recommendations follow:

• Women between the ages of 40 and 50 should discuss with their doctors the benefits and harms of mammograms, as well as when to start and how often to have them based on their family history and any additional risk factors.
• Some organizations recommend women have mammograms every 1 to 2 years, starting at age 40. Others recommend mammograms starting at age 50.
• Women in good health should have a routine mammogram at least every two years between 50 to 74. Women age 75 and older should talk to their doctors about whether they need continued screenings.

About 5% - 10% of mammograms require further testing. This may include an additional mammogram view or a different test, such as an ultrasound, biopsy tissue sampling or MRI. Not all mammograms that show an irregularity indicate cancer. In fact, further testing after an irregular mammogram shows no cancer in most cases. Young women in particular have higher rates of these types of results, called “false positives”.

Preparation
A mammogram is often uncomfortable but rarely painful. If you have sensitive skin, fragile skin or a skin condition, let your technician know before your exam. If you have menstrual periods, the procedure is more comfortable when done within the week after your last period, especially if your breasts become tender before your period starts.

The X-ray plate will feel cold when you place your breast on it. Having your breasts flattened and squeezed is necessary to flatten out the breast tissue and obtain the best pictures.

Tell your health professional if you:

• Are or might be pregnant. A mammogram is not done for routine screening during pregnancy due to exposure to low-dose radiation.
• Are breastfeeding. A mammogram may not provide clear results in breasts that contain milk.
• Have breast implants. Breast implants require a modified mammogram method.
• Have previously had a breast biopsy. Knowing the location of scar tissue will help the radiologist read your mammogram accurately.

On the day of the mammogram, do not use deodorant, perfume, powders, or ointments on your breasts. The residue left on your skin by these substances may interfere with the X-rays.

If you have previously had a mammogram done at another clinic, have the results sent or bring them with you to your examination.