May 4, 2009

Breastfeeding Moms Have Lower Heart Risks Later in Life

Photo of a woman holding an infant

The longer moms breastfeed their babies, the less likely they are to have cardiovascular disease and related risk factors after their childbearing years, a new study suggests.

Breastfeeding is well known to offer many benefits to babies, including a complex balance of nutrients and protection against infections. In recent years, a growing body of research has linked breastfeeding to reduced health risks for mothers as well. Some studies have found that breast, uterine and other types of cancer occur less often in women who've breastfed their babies. Other research has linked breastfeeding to a lower risk for diabetes.

In the latest study, investigators led by Dr. Eleanor Bimla Schwarz of the University of Pittsburgh examined data from nearly 140,000 postmenopausal women. The women were participants in the Women's Health Initiative study funded by NIH's National Heart, Lung and Blood Institute (NHLBI). Support for the analysis came from both NHLBI and NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).

When the study began, the women were 50 to 79 years old. All had previously given birth. About 60% reported that they'd breast-fed at least 1 of their children. The women estimated the total number of months spent breastfeeding all their offspring. On average, it had been 35 years since they'd last breastfed their children. Follow-up evaluations continued for about 8 years.

In the May 2009 issue of Obstetrics and Gynecology, the researchers reported that women who had longer histories of breastfeeding had significantly lower rates of cardiovascular risk factors even after adjusting for family history, lifestyle, body mass index (a ratio of weight to height) and other variables.

Women who breastfed their children for at least 1 month were less likely to have high blood pressure, diabetes or high cholesterol compared to those who had never breastfed. In addition, among women who had only 1 child, those who breastfed for 7-12 months were significantly less likely to develop cardiovascular disease during the follow-up period than women who never breastfed.

Overall, moms who breastfed for a year or more were about 10% less likely to have developed cardiovascular disease than those who had never breastfed. Obesity rates were similar in the 2 groups.

The study has a few limitations despite its large size. It's impossible to know for sure if breastfeeding itself caused the reduction in heart risks or if women at greatest risk for heart disease were less likely to breastfeed. In addition, perhaps more health-conscious women, or those with less stressful lives, were more likely to breastfeed their babies, which could confound the results. Another limitation is that the analysis relied on women's memories of their breastfeeding behaviors decades earlier.

Nevertheless, this study adds to mounting evidence that breastfeeding may provide health benefits to both mothers and their babies.

—by Vicki Contie

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