The Association Between Breastfeeding and Maternal Risk of Heart Disease
by Anne Eglash MD, IBCLC, FABM
The article for this week focuses on a large systematic review and meta-analysis on the maternal risk of heart disease in association with breastfeeding history. The media gave this topic significant attention last week.
In the last 13 years several research studies have been published documenting an association between lower maternal cardiovascular risk in association with breastfeeding. In fact, the 2021 Scientific Statement of the American Heart Association on Cardiovascular Disease Prevention in Women concluded that lactation and breastfeeding may lower a woman’s later cardiometabolic risk.
The goal of this meta-analysis was to more precisely describe the relationship between breastfeeding and risk of heart disease by pooling data from 8 studies, totaling 1,192,700 parous women. Baseline data was collected between 1986-2009, when the subjects were an average of 51.3 years of age. Their mean lifetime duration of breastfeeding was 15.6 months. The researchers found that women who ever breastfed had an 11% decreased relative risk of cardiovascular events, including coronary heart disease, stroke, and fatal cardiovascular disease events. The risk for these diseases decreased further with longer duration of breastfeeding, for up to 12 months cumulative years of breastfeeding.
- Oxytocin is associated with lower blood pressure, lower fat mass, and reduced risk of diabetes.
- Lactoferrin in breastmilk reduces inflammation in the mother's arteries.
- Breastfeeding women have more weight loss postpartum than women who don't breastfeed.
- Breastfeeding helps to reset the metabolism, by improving blood sugar and cholesterol metabolism.
- Breastfeeding reduces the risk of type 2 diabetes later in life.
- Breastfeeding women drink less coffee, which is a risk factor for heart disease.
See the Answer
Breastfeeding has been robustly linked to reduced maternal risk of breast cancer, ovarian cancer, and type 2 diabetes. We herein systematically reviewed the published evidence on the association of breastfeeding with maternal risk of cardiovascular disease (CVD) outcomes.
Methods and Results
Our systematic search of PubMed and Web of Science of articles published up to April 16, 2021, identified 8 relevant prospective studies involving 1 192 700 parous women (weighted mean age: 51.3 years at study entry, 24.6 years at first birth; weighted mean number of births: 2.3). A total of 982 566 women (82%) reported having ever breastfed (weighted mean lifetime duration of breastfeeding: 15.6 months). During a weighted median follow-up of 10.3 years, 54 226 CVD, 26 913 coronary heart disease, 30 843 stroke, and 10 766 fatal CVD events were recorded. In a random-effects metaanalysis, the pooled multivariable-adjusted hazard ratios comparing parous women who ever breastfed to those who never breastfed were 0.89 for CVD (95% CI, 0.83–0.95; I2=79.4%), 0.86 for coronary heart disease (95% CI, 0.78–0.95; I2=79.7%), 0.88 for stroke (95% CI, 0.79–0.99; I2=79.6%), and 0.83 for fatal CVD (95% CI, 0.76–0.92; I2=47.7%). The quality of the evidence assessed with the Grading of Recommendations Assessment, Development, and Evaluation tool ranged from very low to moderate, which was mainly driven by high between-studies heterogeneity. Strengths of associations did not differ by mean age at study entry, median follow-up duration, mean parity, level of adjustment, study quality, or geographical region. A progressive risk reduction of all CVD outcomes with lifetime durations of breastfeeding from 0 up to 12 months was found, with some uncertainty about shapes of associations for longer durations.
Breastfeeding was associated with reduced maternal risk of CVD outcomes.
There is no theory that I am aware of that the components of breastmilk actually affect the maternal risk of cardiovascular events. In addition, I am not aware that breastfeeding women drink less coffee. Even if they do, drinking coffee is not considered a cardiovascular risk for those without cardiovascular disease.
When having conversations with families about the timing of weaning, health professionals and families often focus on the risk of premature weaning for the infant. However, heart disease is the #1 cause of death among women in high-income countries, and high blood pressure and diabetes contribute to significant pathology such as kidney disease and dementia. We need to shed light on the importance of breastfeeding for long term maternal health. This may have an impact on the family's feeding decision.