Placenta Size May Affect Breast Cancer Risk

The heavier the placenta during pregnancy, the greater a woman's risk of breast cancer before menopause, a new Swedish study suggests. "Compared with mothers whose placenta at first delivery weighed less than 500 grams, women whose placenta weighed equal to or greater than 700 grams had a 38 percent increase in risk of breast cancer," said study author Dr. Sven Cnattingius, a professor at the Karolinska Institute in Stockholm. Results of the study are published in the Nov. 16 issue of the Journal of the American Medical Association.