Mammography is an x-ray examination of the breasts to detect abnormalities. The procedure involves positioning each breast on a compression paddle that applies pressure to flatten the breast for imaging. Patients should schedule mammograms when their breasts are least tender, usually after their period, and prepare by avoiding caffeine for several days before and not wearing any lotions or powders the morning of the test. The test involves separately compressing each breast with the x-ray machine and may cause some discomfort during the 15 minute procedure.