Purpose: Preterm birth remains a leading cause of long-term neurodevelopmental impairment, yet early evaluations frequently underestimate subsequent deficits. This study examined longitudinal neurodevelopmental trajectories across gestational age groups and identified predictors of developmental delay. Methods: A retrospective cohort of 532 preterm children, stratified by gestational age, was followed from the neonatal period to early preschool age. Neurodevelopment was assessed using the Korean version of the Bayley Scales of Infant and Toddler Development, Third Edition at 8–12 months (n=481), 13–24 months (n=118), and 25–42 months (n=100). Longitudinal trajectories were analyzed using general linear models, and predictors of developmental delay were identified through multivariable logistic regression. Results: During the first year, motor scores differed significantly across gestational age groups, with extremely preterm infants showing the lowest values. By the third to fourth years of life, cognitive and language scores diverged markedly, with extremely preterm children exhibiting the steepest decline and additional deficits in motor and adaptive behavior domains. Lower gestational age remained an independent predictor of both cognitive and language delay at early preschool age, while no independent predictors were identified for motor, social-emotional, or adaptive behavior outcomes. Conclusion Neurodevelopmental outcomes in preterm children follow dynamic, domain-specific trajectories influenced by gestational age and developmental timing. Motor delays are most evident in infancy, whereas cognitive and language impairments emerge by early preschool age. Gestational age remains a consistent predictor of later delay, emphasizing the need for longitudinal, gestational age–stratified monitoring and early, targeted intervention.

Regular transfusion therapy in children with intractable hematologic disorder results in hemosiderosis. It causes several organ damages such as liver, heart, and endocrine system and increases risk of infection. Thus, iron-chelating therapy is essential to promote normal development, prevent excess iron overload and death in children. In abroad, deferiprone has been approved for use in thalassemic children with transfusion induced iron overload. Side effects associated with deferiprone include agranulocytosis, arthropathy, gastrointestinal symptoms, increased alanine aminotransferase levels, and zinc deficiency. Arthropathy has been reported to occur approximately 9%–38% of patients. We present an 11-year-old boy patient with hereditary spherocytosis, who experienced arthropathy while under deferiprone therapy.