What happens to your body if you have very poor mammary blood circulation?

Not sure. Not sure this is relevant. Please clarify the question with symptoms etc.
Very unusual. The breasts usually have very robust blood circulation. I have never seen a case of insufficient blood supply to the breast. But, in theory, any part of the body affected by poor circulation could have pain, difficulties with wound healing, etc. Visit your doctor if you are having any breast symptoms for a thorough examination.