Overall and Sex-specific Associations between Fetal Adversity and Child Development at One Year: Evidence from Brazil

Abstract

A growing body of epigenetic research suggests that in-utero adaptations to environmental changes display important sex-specific variation. We test this heterogeneous adaptation hypothesis using data from 900 children born at the University Hospital in São Paulo, Brazil, between October 2013 and April 2014. Adjusted and unadjusted linear models were used to quantify the associations between prematurity, small for gestational age and children's physical and mental development at 12 months of age. Prematurity was negatively associated with neuropsychological development in fully adjusted models (z-score difference -0.42, 95% confidence intervals: -0.71, -0.14), but associations did not vary significantly by sex. For small for gestational age, associations with height-for-age, weight-for-age and neuropsychological development were also negative, but systematically larger for male than for female infants (p-values all <0.05). These results suggest that male fetuses may be more vulnerable to intra-uterine adversity than females; further research will be needed to better understand the mechanisms underlying these sex-specific associations.