Early postnatal effects of maternal obesity on breast milk composition and breastfeeding outcomes

Background & aims: Breastfeeding can be challenging in mothers with overweight or obesity-related chronic low-grade inflammation, resulting in negative consequences for the newborn. The pre- gestational body mass index is negatively associated with lactogenesis II, the onset of colostrum secretion. Herein, we evaluated mothers' inflammation, metabolic status, and components of breast milk after birth to associate these factors with their nutritional and breastfeeding status. Methods: The study included volunteer mothers, categorized based on their nutritional status and anthropometric parameters, who gave birth in a tertiary maternity hospital. Serum and breast milk samples were collected 24 and 48 h after birth to determine inflammatory biomarkers (SAA, leptin, CRP, IL-1b, TNF-a, IL-8, IL-6, MCP-1, IL-10, and IFN-g), reproductive hormones (prolactin and progesterone), as well as the breast milk composition (total protein, fatty acid, percentage of fat and Kcal). Furthermore, we conducted a six-month follow-up to assess breastfeeding outcomes. Interestingly, the composition of breast milk did not vary in the different situations analyzed, indicating the stability of the breast milk's composition in meeting infant needs, regardless of age, nutritional status, and type of birth. Results: Our findings revealed a higher concentration of pro-inflammatory biomarkers (SAA, CRP, TNF-a, IL-8, and IFN-g) than anti-inflammatory, IL-10, in breast milk. Our study showed that mothers who were overweight after pregnancy had a newborn with a higher birth weight compared to healthy post- pregnancy weight. Our study elucidates the intricate dynamics between maternal weight, inflammation, and breastfeeding outcomes. Conclusions: While maternal overweight or obesity-related inflammation may pose challenges to lactogenesis II and influence newborn birth weight, breast milk remains a stable and reliable source of essential nutrients for infant nourishment. However, the presence of pro-inflammatory biomarkers in breast milk warrants further investigation into its potential implications for infant health. Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism.