What can affect mammogram results?

Several different things can affect a mammogram and the accuracy of results. They include:

•  Applying deodorant, perfume, lotion or powder to skin before a mammogram. These substances can cause shadows to show up on the mammogram.
•  Dense breasts, particularly in young women, can make finding abnormal lesions or cancer more difficult.
•  Use of hormone therapy, which can make breasts more dense, and make finding cancer more difficult.
•  The menstrual cycle. Breasts are more dense in the week before menstruation begins, which can make cancer trickier to detect and may make getting the mammogram more uncomfortable than it would be a week after a period begins.
•  Breastfeeding, which causes changes in the breast that make detecting cancer on a mammogram more difficult.