Breastfeeding not only benefits babies; it also may lower the risk for a heart attack or stroke later in life for mothers who breastfeed more than for women who don’t.
The findings, which were published online June 21 in the Journal of the American Heart Association, are based on data from a prospective study of nearly 300,000 women in China.
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To assess the impact of breastfeeding on maternal cardiovascular health, the researchers reviewed data from 289,573 women who were participating in the China Kadoorie Biobank study to assess their reproductive history and lifestyle. At the time of study enrollment, none of the women had a history of cardiovascular disease and 99% reported at least one live birth. The average age of the women at baseline was 51 years.
Of the women who had given birth, 97% reported ever breastfeeding, and 91% reported breastfeeding each child for at least 6 months. The median duration of breastfeeding was 12 months per child (J Am Heart Assoc. 2017 Jun 21. doi: JAHA/2017/006081-T2).
During an 8-year follow-up period, participants experienced 16,671 cases of coronary heart disease and 23,983 strokes.
Overall, women who breastfed babies had a 9% reduction in risk of coronary heart disease and an 8% reduction in risk of stroke, compared with women who never breastfed. The longer the duration of breastfeeding, the greater the risk reduction; for every additional 6 months of breastfeeding, researchers found a 4% reduction in heart disease risk and a 3% reduction in stroke risk. Mothers who breastfed for 2 years or more had the most protection – an 18% reduced risk of heart disease and a 17% reduced risk of stroke, compared with mothers who never breastfed.
The study was limited by several factors, including its observational nature, which cannot confirm a causal relationship between breastfeeding and CVD. However, the results suggest that, if causal, “interventions to increase the likelihood and duration of breastfeeding could have persistent benefits to maternal cardiovascular health,” they wrote.
The baseline study was funded by the Kadoorie Charitable Foundation in Hong Kong; long-term support came from the UK Wellcome Trust, Chinese Ministry of Science and Technology, and the Chinese National Natural Science Foundation. Other support came from the British Heart Foundation, UK Medical Research Council and Cancer Research UK, and the National Natural Science Foundation of China. Dr. Peters has received support from the British Heart Foundation.