Gestational age at birth and cognitive outcomes in term-born children: Evidence from Chinese and British cohorts

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Older gestational age (GA) can lead to favourable cognitive outcomes in preterm children. Recent evidence suggests this may also apply in term-born children. This study aims to examine the association between GA and early developmental outcomes in children born at term in China and the UK. Participants were term-born children from two cohorts, the Sichuan Multi-stratified Infants and Early Life (SMILE) study in China and the Developing Human Connectome Project (dHCP) in the UK. Early cognitive outcomes were assessed at 6 months in the SMILE study, and at 18 months in the dHCP. Linear regression models were conducted to examine the association between GA at birth and early cognitive outcomes for each cohort separately. A final sample of 1245 participants from the SMILE study and 406 participants for the dHCP were included in the analysis. In the SMILE study, longer GA was associated with better mental developmental (B = 2.47 [1.60, 3.34], P < .001) and psychomotor outcomes (B = 2.91 [2.01, 3.82], P < .001), after controlling for sex, parental education, family yearly income, maternal age, maternal depressive symptoms, and birth weight; in the dHCP, longer GA was associated with better cognitive (B = 1.35 [0.33, 2.37], P = .010) and motor developmental outcomes (B = 1.49 [0.59, 2.39], P = .001), after controlling for sex, relative social deprivation, maternal depressive symptoms and birth weight. Toddlers born at term can benefit from longer GA with more favourable early developmental outcomes. These findings were consistent in two birth cohorts from the UK and China, providing cross-cultural evidence of robust extrapolation. • Toddlerhood development among term-born children still benefits from older gestational age. • The association between gestational age and developmental outcomes applies to both Chinese and UK contexts. • Higher socioeconomic status and females were associated with better cognitive and language development. • Higher maternal depressive symptoms were associated with poorer language development.