Dense breast tissue is seen on a mammogram. There are different types of tissue inside your breasts. Some breast tissue is fatty. Other breast tissue is dense. "Dense" means it has more milk glands, milk ducts, and fibrous tissue than fatty tissue. It is common to have dense breasts.

Dense breast tissue and fatty breast tissue are both normal. You cannot tell how dense breasts are by their size or firmness. Your mammogram report will tell you if you have dense breasts.

Things that can affect breast density include genetics, being pregnant or breastfeeding, and using estrogen hormone therapy. Age also affects breast density. Younger people are more likely to have dense breasts than older people.