What is breast density and why does it matter?All breasts are made up of a mix of fat, milk glands and ducts. The glands are supported by fibrous tissue and ligaments, collectively called “fibroglandular tissue.” The more fibroglandular tissue a woman has, the “denser” her breast tissue.When a woman has a mammogram, the radiologist reviewing it will describe her breast density using one of four categories: A) fatty, B) scattered tissue, C) heterogeneously dense or D) extremely dense. Categories C and D are considered “dense” whereas categories A and B are “not dense.”Dense breasts are normal and common. Over 50% of women have dense breasts before menopause, as do about 40% of women in their 50s and 30% of women in their 60s. Breasts can become less dense after menopause, but a woman with extremely dense breasts will likely continue to have dense breasts all her life.
