Human milk phospholipids across lactation stages and their associations with infant neurodevelopment: a prospective cohort study in China.

Introduction: Early-life nutrition is a key determinant of infant neurodevelopment. Phospholipids (PLs) in human milk contribute to neuronal membrane structure and signaling, yet population-based evidence linking milk PLs to early neurodevelopment remains limited. This study aimed to examine dynamic changes in breast milk PLs across lactation and their associations with infant neurodevelopment at 6 months. Methods: In this prospective cohort study, 50 mother-infant dyads were recruited at Peking University People's Hospital. Human milk samples were collected at four lactation stages: colostrum (2 days), transitional milk (15 days), 1-month mature milk, and 6-month mature milk. PL concentrations were quantified using UPLC-MS/MS. Infant neurodevelopment at 6 months was assessed using the Ages and Stages Questionnaires (ASQ-3). Associations between milk PLs and neurodevelopment were analyzed using multivariable linear regression, with Elastic Net regression and bootstrap resampling applied to identify PLs most stably associated with neurodevelopment. Sensitivity analyses including additional PLs (PS and PA) were conducted to evaluate the robustness of findings. Results: A total of 148 PL species across 13 classes were quantified. Total PL decreased from colostrum to mature milk, with distinct patterns observed for individual subclasses. In multivariable regression, higher LPC and Cer in colostrum and PI in 1-month mature milk were positively associated with ASQ-3 scores. Elastic Net analysis highlighted several PLs in colostrum with relatively higher selection probabilities. Joint modeling revealed that Cer, LPC, and PC were positively associated with neurodevelopment, whereas PE was negatively associated. Conclusion: Breast milk PLs exhibit marked temporal variations across lactation, and early-lactation PLs, particularly in colostrum, are associated with infant neurodevelopment at 6 months. These findings underscore the potential importance of colostrum PLs in early brain development and highlight the need for further studies with larger cohorts, longer follow-up, and molecular-level lipidomic analyses.