Breastfeeding is associated with a reduced maternal risk for cardiovascular disease (CVD) outcomes, according to a study published in the Journal of the American Heart Association.
Investigators conducted a systematic literature review and meta-analysis to evaluate the association between breastfeeding and development of maternal cardiovascular events.
They searched PubMed and Web of Science for articles published up to April 16, 2021, and selected 11 articles on 8 distinct and relevant prospective studies. The studies included 1,192,700 parous women, with a mean age of 51.3 years at study entry, aged 24.6 years at first birth, and a weighted mean of 2.3 births.
Among the cohort, 982,566 (82%) women reported that they had ever breastfed, and the weighted mean lifetime breastfeeding duration was 15.6 months. After a weighted median follow-up of 10.3 years, the studies reported 54,226 incident maternal CVD events, 26,913 incident maternal coronary heart disease (CHD) events, 30,843 incident maternal strokes, and 10,766 maternal fatal CVD events. The studies were generally of high quality, with a weighted overall mean Newcastle-Ottawa Scale (NOS) score of 6.5.
In a comparison of women who ever breastfed with those who never breastfed, hazard ratios were 0.89 for maternal CVD (95% CI, 0.83-0.95; I2 = 79.4% [95% CI, 57.8%-89.9%]); 0.86 for maternal CHD (0.78-0.95; I2 = 79.7% [55.8%-90.7%]); 0.88 for maternal stroke (0.79-0.99; I2 = 79.6% [51.6%-91.4%]); and 0.83 for maternal fatal CVD (0.76-0.92; I2 = 47.7% [0.0%-79.3%]), according to random-effects meta-analysis.
Fixed-effects meta-analysis showed corresponding pooled hazard ratios of 0.95 for CVD (0.92-0.97), 0.91 for CHD (0.88-0.94), 0.90 for stroke (0.86-0.94), and 0.87 for fatal CVD (0.82-0.92).
The quality of the evidence ranged from very low to moderate, based on the Grading of Recommendations Assessment, Development, and Evaluation. The strengths of the associations were not different regarding mean age at baseline, median follow-up duration, mean parity, level of adjustment, higher vs lower NOS, or in a comparison with studies conducted in Asia vs those from other geographic regions.
The investigators noted that their findings need to be interpreted with caution because they are based on fewer than 10 studies. Also, significant between-studies heterogeneity occurred regarding the outcomes of CVD, CHD, and stroke. Furthermore, breastfeeding was self-reported in all studies and was recalled several years after the breastfeeding period.
“We found a significantly decreased risk for maternal CVD, CHD, stroke, and fatal CVD for lifetime durations of breastfeeding for up to 12 months,” the researchers wrote. “After this time, the effect on CHD appeared to reach a plateau between 12 and 48 months.”
Tschiderer L, Seekircher L, Kunutsor S, Peters S, O’Keeffe L, Willeit P. Breastfeeding is associated with a reduced maternal cardiovascular risk: systematic review and meta-analysis involving data from eight studies and 1,192,700 parous women. J Am Heart Assoc. Published online January 11, 2022. doi: 10.1161/JAHA.121.022746