Mothers who don’t breastfeed their newborns for at least one month are more likely to develop type 2 diabetes at some point in their lives than women who do, a Pennsylvania study finds.

Previous research demonstrated health benefits to moms who breastfed as long as six months or a year. The Pennsylvania results suggest that even a month of breastfeeding can have positive, lasting effects.

“What we found that was somewhat surprising was the pretty dramatic benefits for moms who breastfed as short as a month after the birth of their child,” the lead author, Dr. Eleanor Schwarz of the University of Pittsburgh, told Reuters Health.

In type 2 diabetes, the most common form of the disease, either the body does not produce enough insulin or the cells ignore the insulin that the body needs to turn food into energy. An estimated 10 percent of American women have it.

To see how long a new mom needs to breastfeed to reap later benefits to her health, Schwarz and colleagues analyzed a large database of patients treated by Kaiser Permanente Medical Care Program of Northern California.

They compared the incidence of type 2 diabetes in 2,233 women between the ages of 40 and 78, divided into three groups: those who had never had children (405 women), those who had children but never breastfed them (703 women) and those who had breastfed (1,125 women).

The researchers found that 188 (26.7 percent) of the study mothers who didn’t breastfeed their infants later went on to develop diabetes compared to 202 (18 percent) of women who exclusively breastfed their newborn at least one month and 71 (17.5 percent) of women who never had children.

The findings “highlight the importance to maternal health of consistent lactation after each birth” and add to the growing body of evidence that not breastfeeding might add to health risks.

“Women who give birth but do not breastfeed face an increased risk of developing type 2 diabetes,” the authors conclude in the September 9 issue of the American Journal of Medicine.

Why this is so, they point out, is not known. Animal studies have shown that the formation and secretion of milk by the mammary glands (lactation) may itself start biological processes that increase sensitivity to insulin and reduce the formation of belly fat.

“Breastfeeding is part of the normal recovery process” from pregnancy and giving birth, Schwarz said.

Yet only about 14% of new mothers in the US managed to follow the American Academy of Pediatrics’ recommendation to exclusively breastfeed their infants for the first 6 months.

The study results tell new mothers that they can do something for their own health by breastfeeding for at least a month, Schwarz said. The authors also have a message for moms who, for whatever reason, never breastfed their children.

“They should talk to their doctor about what steps they can take to modify their own risk of developing diabetes, because it seems they are probably at higher risk than other women in the community,” Schwarz said.

The authors urge “ongoing support of breastfeeding” from doctors, legislators and employers.

SOURCE:  The American Journal of Medicine, September 2010.