Major health organizations recommend that infants breastfeed for the first two years of life; however, breastfeeding rates for children at 12 months of age are below 20 percent in most industrialized countries. Much of the public health messaging surrounding the benefits of breastfeeding have focused on improved health outcomes for infants. Findings of a new report show that mothers benefit from breastfeeding as well by experiencing reduced cardiovascular disease risk later in life.

Breastfeeding produces many physiological and psychological effects for the mother, many of which are facilitated by the release of hormones such as oxytocin. Previous research has demonstrated that oxytocin has beneficial effects on the cardiovascular system, including lowering blood pressure, improving glucose tolerance, increasing antioxidant capacity, resolving inflammation, and reducing body fat stores. However, additional large-scale studies are needed to better understand how breastfeeding affects mothers long-term.

The authors conducted a systematic review and meta-analysis. First, they searched the scientific literature for studies observing the effects of breastfeeding duration on one or more markers of cardiovascular disease risk. Next, they filtered their results based on a set of criteria designed to identify studies of high quality. Finally, they combined data from these high-quality studies and reanalyzed it so they could interpret the results on a large scale.

The systematic review yielded eight relevant studies that included over one million mothers (average age, 51 years). Mothers who breastfed for any length of time had an 11 percent lower cardiovascular disease risk, 14 percent lower coronary heart disease risk, 12 percent lower stroke risk, and 17 percent lower risk of cardiac death compared to mothers who never breastfed. These results were dose-dependent, meaning that the reduction in disease risk increased as the length of breastfeeding increased, but only up to 12 months. Additional long-term data are needed to determine if breastfeeding longer than 12 months provides additional cardiovascular disease risk-lowering benefits.

The results of this large-scale meta-analyses provide evidence that breastfeeding reduces risk for multiple cardiovascular diseases in a dose-dependent way, although additional data are needed to understand the cardiovascular benefits of breastfeeding beyond 12 months.

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• Learn more about the biology of breast milk and breastfeeding from our overview article on the topic.