Researchers confirm the lower risk of breast cancer from multiple pregnancies and from breast feeding seen in average risk women extends to those at the highest risk of breast cancer, according to the largest prospective study of BRCA1 and BRCA2 mutations carriers to date. Women with BRCA1 mutations who had two, three or four or more full-term pregnancies were at 21 percent, 30 percent, and 50 percent decrease risk of breast cancer compared to women with a single full-term pregnancy.