Among 92,551 term-born children (37–41 weeks) from the Norwegian MoBa cohort, this study compared how gestational age and fetal size (SGA, AGA, LGA) independently associate with neurodevelopment from infancy through adolescence, using parent-reported language/motor milestones at 6, 18 months, 3, and 5 years, and national test scores in Math, Reading, and English at grades 5, 8, and 9.
Earlier term birth was linked to worse early language and motor development, but effects faded by age 5. SGA had a more durable impact: lower math scores persisted into adolescence at ages 10–11 (β = −2.32), 13–14 (β = −1.79), and 14–15 years (β = −1.85). Gestational age and fetal size effects were statistically independent.
Outcomes relied partly on parent-reported developmental milestones, which may introduce reporting bias. The cohort is Norwegian, limiting generalizability to other populations. Congenital malformations were excluded, but other unmeasured confounders (e.g., socioeconomic factors, parental IQ) may persist.
When counseling families after a term birth, treat fetal size and gestational age as separate risk signals — SGA carries lasting academic risk into adolescence, while early-term gestational age effects largely resolve by age 5. Do not use gestational age alone as a proxy for long-term neurodevelopmental risk in term-born children.
