Small for Gestational Age - Cognitive Performance From Infancy to Adulthood: An Observational Study
To determine whether cognitive performance from infancy to adulthood is affected by being born SGA, and if this depends on the SGA reference used. Furthermore, to determine SGA's effect while considering the effects of very preterm/very low birth weight (VP/VLBW), socioeconomic status (SES), and parent-infant relationship.
Design, setting and population:
414 participants (197 Term-Born, 217 VP/VLBW) of the Bavarian Longitudinal Study METHODS: SGA was classified using neonatal or fetal growth references. SES and the parent-infant relationship were assessed before 5 months old.
Main outcome measures: Developmental (DQ) and IQ tests assessed cognitive performance on 6 occasions, from 5-months to 26-years old.
The fetal reference classified more infants as SGA (<10th centile) than the neonatal reference (n = 138, 33% versus n = 75, 18%).
Using linear mixed models, SGA was associated with IQ -8 points lower than appropriate for gestational age, regardless of reference used (95% CI -13.66 to -0.64 and 95% CI -13.75 to -1.98). This difference narrowed minimally into adulthood.
Being VP/VLBW was associated with IQ -16 (95% CI -21.01 to -10.04) points lower than term-born participants.
Low SES was associated with IQ -14 (95% CI -18.55 to -9.06) points lower than high SES. A poor parent-infant relationship was associated with IQ -10 points lower than those with a good relationship (95% CI -13.91 to -6.47).
SGA is associated with lower IQ throughout development, independent of VP/VLBW birth, low SES or poor parent-child relationship. Social factors have comparable effects on IQ than SGA and should be considered for interventions.
Funding: All authors are supported by EU horizon 2020 grant (RECAP-preterm; www.recap-preterm.eu) under agreement number 733280.
Keywords: Cognition; Cognitive development; IQ; SGA; Small for gestational age; Term; Very preterm; growth restriction.