According to a large study published in the Archives of Internal Medicine, women who had a first-degree relative, such as a sister or mother, with breast cancer had a lower risk of developing the disease if they had ever breastfed than if they had never breastfed. They were 59 percent less likely to develop breast cancer themselves if they breastfed their children.
CBS News medical correspondent and resident OB-GYN Dr. Jennifer Ashton said on "The Early Show" this is a "huge number."
However, the study, which focused on 60,000 women who had given birth at least once, was associative, Ashton said, meaning its raw data results don't show a cause and effect.
She said, "The proposed theory or mechanism that researchers will be looking at in the future is that there's possibly something about engorgement or milk production that (if not stimulated or is suppressed)actually winds up leading to inflammation, and triggering a cascading offense."
Another limitation of the study, Ashton said, is that researchers didn't look at women with BRCA genetic mutations, which puts women at a higher risk for breast cancer. The women in the study, Ashton said, had a first-degree relative, but not that gene.
Beyond lowering the breast cancer risk in some women, Ashton said breastfeeding also has numerous benefits for the mother and baby.
For mothers, breastfeeding your baby for any duration can lower your risk of Type 2 diabetes, accelerates weight loss and reduces your risk of ovarian cancer and cardiovascular disease, she said.
And for a baby, Ashton said breastfeeding reduces the risk of respiratory infections, diabetes and obesity as children grow. She added it's a great bonding opportunity for the mother and child.
But mothers don't actually have to breast feed the baby, Ashton said. Babies, she noted, can get the same benefits from pumping. Mothers, she said, just have to anticipate logistical issues to make sure their baby gets breast milk at regular intervals.