Breastfeeding has long been considered a healthy choice for both mothers and their babies, but new research published this week shows that it could also reduce a woman’s risk of having a heart attack or stroke later in life.

The study, published in the Journal of the American Heart Association, included data from more than 289,000 women in the China Kadoorie Biobank study who provided information about their reproductive history and lifestyle.

When the observational study began, none of the women had cardiovascular disease, but after eight years, there were 16,671 cases of coronary heart disease.

Study results showed mothers who breastfed had a 9 percent lower risk of heart disease and an 8 percent lower risk of stroke, compared to women who never breastfed. Women who breastfed each of their children for two years or more had a 18 percent lower risk of heart disease and a 17 percent lower risk of stroke. Overall, each additional six months of breastfeeding per child was linked to a 4 percent lower risk of heart disease and a 3 percent lower risk of stroke.

“The health benefits to the mother from breastfeeding may be explained by a faster ‘reset’ of the mother’s metabolism after pregnancy,” said study co-author Sanne Peters, PhD, a research fellow at Oxford University in England, in an AHA statement. “Pregnancy changes a woman’s metabolism dramatically as she stores fat to provide the energy necessary for her baby’s growth and for breastfeeding once the baby is born. Breastfeeding could eliminate the stored fat faster and more completely.”

The study is limited by being observational and depending on the honesty of patients since they self-report information. Because of this, the researchers recommend that more studies be done to verify the results.

The AHA recommends that women breastfeed their babies for one year, though only about half are still breastfeeding after six months, according to the Centers for Disease Control and Prevention.

“Although there is increasing recognition of the importance of exclusive breastfeeding, genuine commitment from policy makers is needed to implement strategies in the health care system, communities and families, and the work environment that promote and support every woman to breastfeed," the authors wrote in the study. "If effective and sustained, such efforts are likely to confer major benefits to the health of children and women, along with substantial cost savings.”