Exposure to Microplastics in Biological Matrices and Neurodevelopmental Outcomes in Children: A Systematic Review

Micro- and nanoplastics (MNPs) are ubiquitous environmental contaminants detected in numerous human tissues, yet epidemiological evidence on MNPs exposure and neurodevelopmental outcomes in children has not been systematically evaluated. We aimed to systematically identify, appraise, and synthesize observational evidence on this association in children aged 0-18 years. Six databases were searched on 19 February 2026 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines (PROSPERO: CRD420261328979). Risk of bias and certainty of evidence were assessed using Joanna Briggs Institute (JBI) checklists and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) framework. Three studies met the inclusion criteria (all published in 2025, China; n = 30-5670; two studies with probable population overlap), addressing behavioral, cognitive, and neurological outcome domains, encompassing 56 associations across 14 outcomes. Each study showed a uniform direction of association (higher MP exposure was associated with poorer outcomes); however, probable population overlap between Dong and Zheng precludes interpretation of this pattern as independent cross-study replication. All outcomes were rated Very Low certainty under GRADE; meta-analysis was not performed. Although experimental evidence supports biological plausibility, no causal inferences can be drawn in the absence of independent replication, and the field remains at the stage of hypothesis generation. Future studies should prioritize prospective longitudinal designs, spectroscopic exposure confirmation, and standardized neurodevelopmental outcomes.