What does it mean to have dense breasts?

And should I be worried because of that? I had my first mammogram when I turned 45. The results were hard to read because of the denseness of my breasts. I had to have an ultrasound shortly afterwards to make sure that the calcification they found was just that and nothing more. Plus, they had to establish a baseline. Since then I have had to go once a year and each time I also have to have an ultrasound and all because my breasts are dense! But what exactly does that mean? What causes the denseness? I would also like to know if it's a negative thing and if there is anything I can do to make them less dense? I hope you can help.

Minnieee

F, 48, Pennsylvania

Dense breasts refers to breasts that have little fatty tissue relative to the breast tissue present.  The issue with having dense breasts is that it makes it harder to feel lumps on self exams, and it may make it harder to determine the significance of things that may show up on mammograms requiring further studies like ultrasounds (which you've already experienced).  It is important that you continue to be followed, which you apparently are.  There's nothing that can be done to decrease the denseness of your breasts.