A mammogram requires compressing the breast between two plastic plates and taking an X-ray. Breast compression is necessary to achieve the highest possible detail. As the breast is compressed, the tissue is better visualized and at the same time the radiation dose to the breast is reduced. Many women have no discomfort. Some women experience mild discomfort as a result of pressure exerted on your breast by the plates. For some women it helps to schedule your mammogram during a time in your cycle when you know your breasts are not tender.
Some women are concerned about radiation exposure during mammography, but studies have shown that such risks with state-of-the-art mammography equipment are minimal and far outweighed by the benefits of a thorough procedure.