Relationship between gestational age and neurodevelopmental disorders

Objective: To investigate neurodevelopmental disorders (NDDs) risks across different gestational ages (GAs) and associated characteristics in infants followed to age 10. Study design: This nationwide, longitudinal, retrospective cohort study analyzed 1288347 live births in Taiwan from 2009 to 2016 by using national health databases. Infants were categorized by GA (extremely preterm, very preterm, moderate to late preterm, fullterm, and late-term) and monitored for 7 NDDs through 2019. Demographic characteristics were compared using the standardized mean difference (SMD). Multivariable Cox regression models were used to estimate hazard ratios with 95% confidence intervals, and the Kaplan–Meier method with log-rank tests was used to determine cumulative NDD probabilities. A 2-tailed P value of <.05 was considered statistically significant. Results: Preterm infants had significantly higher incidence rates of all NDDs (log-rank P < .001), except for tics and Tourette disorders (TDs), compared with the full-term group. Disorders exhibited distinct temporal patterns: cerebral palsy, epilepsy, and developmental delay emerged predominantly before 24 months, whereas autism spectrum disorder, attention-deficit/hyperactivity disorder, and intellectual disability risks peaked during the preschool years. Tics and TDs followed a distinct trajectory, with minimal variation among the GA groups. Advanced parental age (≥40 years) was associated with shorter gestation (SMD > 0.1). Conclusion: Preterm birth is associated with an increased risk of most NDDs, with phase-specific onset patterns. These findings support the need for GA-stratified and age-tailored monitoring. Early motor and cognitive interventions, along with preschool neurobehavioral support, are essential. Tics and TDs may require distinct etiological frameworks.