increase in breast tissue density

I am 45 and had a routine mammogram done a little over a week ago.  I received a call from my Gynecologist today requesting I have a compression mammogram on my left breast because it increased in density from the last year.  Why would it do that and should I be worried?

[DrBhumikaMD]

Hi,
Increase in density of the breast tissue makes it difficult to visualise the breast tissue clearly on a mammogram. A compression mammogram or USG is then done to see the breast tissue clearly. Some of the causes of increased density of breast tissue include young age, OCP or HRT use.
You should not be worried and discuss this with your radiologist and gynecologist. Ask your doctor what are they suspecting?
Have you noticed any abnormal features like nipple discharge, skin changes, lump etc on breast self exam?
Ask for a copy of the mammogram report and ask the doctor when do you need to follow up again and whether any further investigations need to be done like USG / MRI.
Hope this helps.
Good luck.