Angela E. Lanfranchi, MD has recently published an article in Issues in Law and Medicine to explain from the viewpoint of breast physiology why induced abortion can increase risk of breast cancer.

Dr.  Landranchi says when a woman who completes a full term pregnancy, 85% of her breast tissue becomes mature and resistant to environmental risk factors that would otherwise increase breast cancer risk.   This benefit comes from the fetus who produces hormones that help mature the mother's breast tissue.   When the fetus is aborted before 32 weeks, breast tissue is partially matured and becomes most susceptible to the initiation of breast cancer.

Angela E. Lanfranchi, MD is a board certified surgeon who specializes in breast surgery.   She works at Robert Wood Johnson University Hospital in New Brunswick, New Jersey.  

Some observational studies but not all suggest that induced abortion does not increase risk of breast cancer.     One third of U.S. pregnancies are aborted.   Early abortion costs $350 to 500 per visit.    But after 22 weeks, at least $1000 per abortion would incur.    In total, the U.S. may spend nearly 1 billion on abortion each year.   Abortion as a surgery like all other surgeries is not free of risk or complications.  (David Liu, PHD)

Angela E. Lanfranchi,  Normal breast physiology: the reasons hormonal contraceptives and induced abortion increase breast-cancer risk.  Issues Law Med. 2014 Spring;29(1):135-46.