estational age at birth (GAB) is an important determinant of child health and development. Worldwide, approximately 13 million newborns are born preterm (GAB<37 weeks) annually. 1 Prematurity is associated with morbidity and mortality, 2,3 including neurodevelopmental problems, such as cerebral palsy, intellectual disability, learning disability, and poor motor development. [4][5][6] Preterm birth is reportedly associated with increased risks of attention-deficit/ hyperactivity disorder (ADHD), autism spectrum disorder, [7][8][9] and psychiatric disorders in adulthood. 10 In some countries, postterm birth (GAB≥42 weeks) accounts for up to 10% of births 11 and is associated with adverse birth outcomes, in-creased neonatal mortality, cognitive impairment, and increased risk of ADHD. 12 Few studies 13,14 have investigated the associations of GAB with brain structures despite the dynamic neurodevelopment that occurs during early life. During the third trimester of gestation, there is a 4-fold increase in brain size accompanied by marked growth of brain surface area, resulting in the emergence of sulci and gyri. 15,16 Thus, birth before the presumed optimal gestational duration (approximately 40 weeks) may be associated with disruption of neurodevelopmental processes in late pregnancy that persist during postnatal life. IMPORTANCE Preterm and postterm births are associated with adverse neuropsychiatric outcomes. However, it remains unclear whether variation of gestational age within the 37-to 42-week range of term deliveries is associated with neurodevelopment.OBJECTIVE To investigate the association of gestational age at birth (GAB) with structural brain morphometry in children aged 10 years. DESIGN, SETTING, AND PARTICIPANTSThis population-based cohort study included pregnant women living in Rotterdam, the Netherlands, with an expected delivery date between April 1, 2002, and January 31, 2006. The study evaluated 3079 singleton children with GAB ranging from 26.3 to 43.3 weeks and structural neuroimaging at 10 years of age from the Generation R Study, a longitudinal, population-based prospective birth cohort from early pregnancy onward in Rotterdam. Data analysis was performed from March 1, 2019, to February 28, 2020, and at the time of the revision based on reviewer suggestions. EXPOSURESThe GAB was calculated based on ultrasonographic assessment of crown-rump length (<12 weeks 5 days) or biparietal diameter (Ն12 weeks 5 days) in dedicated research centers.MAIN OUTCOMES AND MEASURES Brain structure, including global and regional brain volumes and surface-based cortical measures (thickness, surface area, and gyrification), was quantified by magnetic resonance imaging. RESULTSIn the 3079 children (1546 [50.2%] female) evaluated at 10 years of age, GAB was linearly associated with global and regional brain volumes. Longer gestational duration was associated with larger brain volumes; for example, every 1-week-longer gestational duration corresponded to an additional 4.5 cm 3 /wk (95% CI, 2.7-6.3 cm 3 /wk) larger total...

(Abstracted from JAMA Pediatr 2020;e202991) Gestational age (GA) at birth is an important factor in child health and neurodevelopment. Yet, few studies have evaluated the associations between GA and brain morphometry.