Associations Between Breastfeeding and Postpartum Allostatic Load: NHANES 1999–2016

OBJECTIVES: Current evidence suggests breastfeeding has a modulating effect on maternal stress. We aimed to examine the association between breastfeeding and maternal allostatic load, a marker of chronic stress and adverse health, among women within one year postpartum, using nationally representative data. We hypothesized that women who were breastfeeding had lower allostatic load compared to women who were not breastfeeding. METHODS: A cross sectional analysis of nine waves of data from the National Health and Nutrition Examination Survey (NHANES 1999–2016) was conducted on a sample of 1203 women >18 years old, within their first year postpartum, who provided information on breastfeeding status through the reproductive health questionnaire. An allostatic load score (range 0–10) was derived for each participant based on ten biomarkers reflecting metabolic, cardiovascular, and immune health. Simple linear regression was used to test bivariate associations between potential confounders and allostatic load. Confounders were then incorporated into multiple linear regression models. The final model tested associations between breastfeeding and allostatic load, adjusting for maternal age, race/ethnicity, education, and poverty status. RESULTS: Our findings showed that breastfeeding had a significant inverse association with allostatic load in unadjusted and adjusted models. Furthermore, controlling for age, race/ethnicity, education, and poverty status, we found that breastfeeding women had 0.2727 points lower allostatic load score than non-breastfeeding women (ß = −0.2727, SE = 0.0958, P = 0.0045). CONCLUSIONS: Our study suggests breastfeeding is protective of maternal stress, demonstrating an inverse association with allostatic load among women during the first year postpartum. Our results provide a more comprehensive picture of breastfeeding's influence on multiple body systems, exemplifying physiological benefits beyond effects on single biomarkers. FUNDING SOURCES: No funding was used to support this study.