“…SIgA serves as a defense against infections, and low salivary sIgA levels are associated with increased likelihood of illness (Jemmott & McClelland, ; Volkmann & Weekes, ). Numerous behavioral immunology studies in adults have shown that psychological distress and stressful experiences reduce breast milk (Groer, Davis, & Steele, ; Kawano & Emori, ) and salivary sIgA (Engeland et al, ; Graham, Chiron, Bartholomeusz, Taboonpong, & Brooy, ; Phillips et al, ; Segerstrom & Miller, ) while the developmental literature consistently shows maternal well‐being is a primary regulator of child development (e.g., Morris, Silk, Steinberg, Myers, & Robinson, ). Our findings extend these two fields revealing the importance of maternal well‐being for infant immunity.…”