The Relationship of Preterm and Small for Gestational Age with Child Cognition During School-Age Years

Abstract

Background: Children born preterm and/or small for gestational age (SGA) are at increased risk of poor cognitive outcomes, particularly in low and middle-income countries (LMICs).

Objectives: This study aimed to examine the cognitive and academic deficits during the school-age years in children born preterm or SGA compared with those in children born term adequate for gestational age (AGA) in rural Vietnam.

Methods: Children born to women in a preconception micronutrient supplementation trial in Vietnam were classified into 3 groups: preterm AGA (n =138), term SGA (n =169), and term AGA (n = 1134). Cognitive abilities were assessed using the Wechsler Intelligence Scale for Children, measuring 4 domains [verbal comprehension index (VCI), perceptual reasoning index (PRI), working memory index (WMI), and processing speed index (PSI) scores] and full-scale intelligence quotient (FSIQ) at 6-7 and 10-11 y. Academic achievement was assessed with mathematic and language tests. Analysis of variance and multiple regression models were used to analyze differences in cognitive function and academic achievement at 6-7 and 10-11 y by birth phenotypes.

Results: Compared with term AGA children, those born SGA had lower cognitive scores at both 6-7 y (VCI, -2.3; PRI, -3.7; PSI -2.1; and FSIQ, -2.9) and 10-11 y (VCI, -3.7; PRI, -3.5; WMI, -2.7; PSI, -1.9; and FSIQ, -3.9). Children born SGA also had poorer academic achievement with lower language (5.3) and mathematic (2.5) scores. Adjustments for maternal factors and home environment attenuated the associations, but the differences in VCI, PRI, FSIQ, and language at 10-11 y remained significant. There were no differences in cognitive function and academic achievement between children born preterm and AGA.

Conclusions: Our findings highlight the enduring association of birth phenotype on cognitive functioning and academic achievement during the school years, despite adjustments for maternal education and family environment. Further research is needed to implement effective interventions to improve birth outcomes and optimize child health and development in LMICs. The trial was registered at clinicaltrials.gov as NCT01665378 (URL: https://clinicaltrials.gov/ct2/show/NCT01665378).

Keywords: Vietnam; academic achievement; cognition; preterm; small for gestational age.