Gestational age and neurodevelopmental outcomes from 1 to 5 years: the PERSIAN birth cohort.

backgroundGestational age (GA) may influence neurodevelopment and behavior, but evidence across the full preterm-to-post-term spectrum in community cohorts remains limited; we hypothesized that associations would be small and age-specific.

methodsWe conducted a secondary analysis of the PERSIAN Birth Cohort (Isfahan, Iran; births 2016-2019). GA was examined continuously and in four categories (preterm, early term, full term, late/post-term). Development was assessed with the Ages and Stages Questionnaire (ASQ) at 12 and 60 months, and behavior with the Child Behavior Checklist (CBCL) at 24 and 48 months. Wave-specific regression models adjusted for maternal, perinatal, delivery, and socioeconomic factors.

resultsAmong 3174 children, GA showed little evidence of association with the ASQ total scores at 1 or 5 years and only small differences in the CBCL total problems scores at 2 years that were not apparent at 4 years. Secondary analyses suggested modest differences concentrated in motor-related ASQ domains and in a subset of CBCL syndrome and DSM-oriented scales at 2 years, particularly among late/post-term children, with most associations attenuated by preschool age.

conclusionIn this cohort, gestational timing explained a small proportion of variation in developmental and behavioral screening outcomes, supporting cautious use of gestational age in developmental surveillance. IMPACT: Across the full preterm-to-post-term spectrum, gestational age showed only modest, age- and domain-specific associations with developmental and behavioral screening outcomes. In a large community-based birth cohort, most associations attenuated by preschool age, reducing concern about broad persistent differences across early childhood. These findings support surveillance-oriented, context-aware use of gestational age in pediatric practice rather than deterministic risk labeling.