Jan. 18, 2022 -- A large study in more than 1 million mothers shows that compared to other women who did not breastfeed their children, those who had breastfed their children had a lower risk of heart disease, stroke, or of death from these diseases later in life.
Over an average follow-up period of about 10 years, the researchers found that women who breastfed their children for any length of time had an 11% lower risk of diseases of the heart or blood vessels, a 14% lower risk of heart disease, a 12% lower risk of stroke, and a 17% lower risk of dying from these diseases.
"We believe that [breastfeeding] benefits for the mother are communicated poorly," lead author Lena Tschiderer, PhD, a postdoctoral researcher, and senior author Peter Willeit, MD, an epidemiologist from the University of Innsbruck, in Austria, told WebMD in a joint email.
"Positive effects of breastfeeding on mothers need to be communicated effectively, awareness for breastfeeding recommendations needs to be raised, and interventions to promote and facilitate breastfeeding need to be implemented and reinforced," they concluded.
"Raising awareness regarding the multifaceted benefits of breastfeeding could be particularly helpful to those mothers who are debating breast vs. bottle feeding," Shelley Miyamoto, MD, a pediatric cardiologist at Children's Hospital Colorado in Aurora, who was not involved with the study, said in a news release from the American Heart Association.
"It should be particularly empowering for a mother to know that by breastfeeding, she is providing the optimal nutrition for her baby while simultaneously lowering her personal risk of heart disease," she said.
Breastfed babies get fewer respiratory infections, like colds and the flu, and have a lower risk of death from infectious disease than other babies, studies have shown.
Women who breastfeed their children have also been shown to be less likely to later get type 2 diabetes, ovarian cancer, or breast cancer.
For this new study, the researchers analyzed results from eight studies in mothers in Australia, China, Japan, Norway, the United States, and Europe.
The women were about 25 years old when they had their first child, and on average, they had two children.
Overall, 82% of the women had breastfed their children at least some of the time. On average, they had breastfed for close to 16 months altogether. (For example, they may have breastfed two children for about 8 months each.)
This amount of time is less than the advice from the World Health Organization. It recommends breastfeeding exclusively until the baby is 6 months old, and then breastfeeding along with other feeding until the infant is 2 years old or more.
But the risk reductions of 11% for diseases of the heart and blood vessels and 14% for heart disease are "impressive numbers," says Roxana Mehran, MD, a cardiologist at Icahn School of Medicine at Mount Sinai in New York City, who was not involved with the study.
The observations in this analysis are very important and should not be ignored, she says.
The beneficial effects of breastfeeding in the mother, she notes, can be linked to hormones, weight loss, and a reset metabolism, as the authors suggest.
Clinicians and employers "must provide ways to educate women about breastfeeding and make it easy for women who are in the workplace to pump, and to provide them with resources," where possible, Mehran says.
"I applaud the authors for shining a spotlight on this important topic," says Michelle O'Donoghue, MD, a cardiologist at Brigham and Women's Hospital and Harvard Medical School, Boston.
"If we want to encourage breastfeeding," she says, "we need to make sure that we put the right supports in place. Women need protected places to breastfeed in the workplace and places to store their milk. Most importantly, women need to be allowed dedicated time to make it happen."