New Studies Show How Moms Also Benefit From Breast-Feeding

— -- Two new studies are adding to a growing body of evidence that breast-feeding is both good for the baby and for the mother.

The studies, which focused on diabetes and cancer, found that women who breast-feed cut their risk of diabetes and cancer compared to women who did not breast-feed.

One study published this week in the Annals of Internal Medicine studied 1,035 women who had developed gestational diabetes while pregnant. The condition is associated with an increased risk of developing Type 2 diabetes post pregnancy. The women in the study, however, were up to 50 percent less likely to develop diabetes later on if they breast-fed their child.

The study's authors explained that lactation improves both insulin sensitivity and metabolism, which could reduce the risk of diabetes.

The study authors said women who breast-fed with "higher intensity and longer duration of lactation," were less likely to develop type 2 diabetes two years later.

Another study published last month in the Annals of Oncology found that women who breast-fed appeared less likely to develop certain kinds of breast cancer.

Researchers looked a compilation of 27 medical studies to see how often women who had breast-fed developed certain types of breast cancer. They found that women who breast-fed were 20 percent less likely to develop “triple negative” breast cancer, a form of cancer that has none of the common hormone markers, such as estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2 (HER2).

Dr. Marisa Weiss, senior author on the cancer study and director of breast health outreach at Lankenau Medical Center in Philadelphia, said researchers are still unsure why breast-feeding seems to protect women from breast cancer but that doctors have theorized that the breast is not fully developed until a woman breast-feeds.

"It's immature," Weiss told ABC News, referring to the breast. "It takes a first full-term pregnancy for it to finally grow up and mature on the inside and take on capability to make milk."

Weiss said while breast-feeding has long been associated with better outcomes for infants, experts are also emphasizing how it can help mothers.

"It’s clearly an important opportunity," Weiss said of hospitals explaining to new moms about the benefits of breast-feeding. "It’s better for the baby and better for the mom."

The American Academy of Pediatrics recommends that mothers breast-feed for at least six months if possible and notes that "each year of breast-feeding has been calculated to result in a 4.3 percent reduction in breast cancer."

Dr. Marjorie Greenfield, professor of obstetrics and gynecology at University Hospitals Case Medical Center in Cleveland, Ohio, said the studies could help more women be informed about their choices.

"I think it’s one more piece of information and I think it’s particularly helpful for women who are overweight and have diabetes," said Greenfield.

She emphasized, however, that women need to be supported in their decision, whether that's breast-feeding or not.