The impact of maternal dietary avoidance during breastfeeding on physical growth and social emotional development in infants with food allergies: a prospective cohort study

Background Maternal dietary avoidance is common during breastfeeding for infants with food allergies (FA), yet its comprehensive impact on infant physical growth and social-emotional development remains unclear. This study aimed to investigate these effects to provide evidence-based clinical dietary guidance. Methods In this prospective cohort study, exclusively breastfed infants under 6 months of age were recruited from the child health care clinic of Children’s Hospital of Chongqing Medical University between October 2023 and February 2025. Participants were classified into a FA group and a non-food allergy (NFA) group. The FA group was subdivided based on the extent of maternal dietary avoidance: avoidance of ≥ 5 or < 5 food types. Follow-ups were conducted every two months from enrollment (4–6 months) until 12 months of age. Data collected included infant weight, length, head circumference, and weight-for-length (W/L) Z-scores (calculated using WHO Anthro software), maternal dietary patterns, allergy symptoms, and Ages & Stages Questionnaires: Social-Emotional (ASQ:SE-2) scores at 8, 10, and 12 months. Statistical analyses involved Chi-square, t-tests, and Generalized Estimating Equation (GEE) models to evaluate longitudinal effects of group and time on outcomes. Regression models assessed the impact of avoidance extent. Results The study included 40 FA and 35 NFA mother-infant pairs. All mothers in the FA group practiced dietary avoidance, with 50.0% avoiding ≥ 5 food types; The most commonly avoided foods were milk/dairy products (85.0%) and shrimp/crab (80.0%). GEE analysis indicated that maternal dietary avoidance significantly impaired infant length growth (P < 0.001) but showed no significant effect on weight, head circumference, or W/L. Furthermore, infants whose mothers avoided ≥ 5 food types had significantly higher ASQ:SE-2 scores (indicating more developmental concerns) than those with less avoidance (P < 0.001). Conclusions Excessive maternal dietary avoidance during breastfeeding may adversely affect linear growth and social-emotional development in infants with FA. Healthcare providers should offer targeted guidance to avoid unnecessary restrictions and support optimal infant health. Trial registration: Chinese Clinical Trial Registry, ChiCTR2500111228. Registered on 28 October 2025. Retrospectively registered.