Gestational age and the risk of autism spectrum disorder in Sweden, Finland, and Norway: A cohort study

[...]with advances in neonatal care, the survival for very preterm babies has improved, but longer-term risks in this group have not been comprehensively investigated. ASD has a male predominance, and size at birth is known to influence ASD risk, with increased risks in children born either small or large for GA [27–29]. [...]sex and size for GA should be considered in analyses of ASD risk by GA. To adjust for differences in birth weight, sex-specific size for GA was calculated as “small for GA” (below or equal to the 10th percentile), “appropriate for GA” (between the 11th and 90th percentile), and “large for GA” (above the 90th percentile) [36]. Cohort characteristics by gestational age (weeks) in 3,526,174 live births. https://doi.org/10.1371/journal.pmed.1003207.t001 Risk of ASD The risk of ASD by GA showed a gradual increase in risk of ASD from GA week 40 to GA week 24, and a small rise between GA week 40 and 44, with statistically significantly higher risk across the range of GA compared to the reference group of infants born week 40.