We conducted meta-analyses of 67 studies on the association between neonatal proxies of impaired gas exchange and intellectual disability (ID) or autism spectrum disorders (ASD). Neonatal acidosis was associated with an odds ratio (OR) of 3.55 [95% confidence interval (95% CI) 2.23-5.49] for ID and an OR of 1.10 (95% CI 0.91-1.31) for ASD. Children with a 5-min Apgar score of <7 had an OR of 5.39 (95% CI 3.84-7.55) for ID and an OR of 1.67 (95 % CI 1.34-2.09) for ASD. O2 treatment was associated with an OR of 4.32 (95% CI 3.23-5.78) for ID and an OR of 2.02 (95% CI 1.45 to 2.83) for ASD. Our meta-analysis demonstrates an increased risk of ID and (to a lesser extent) ASD in children with neonatal hypoxia. Moreover, our findings raise the possibility that concomitant ID might account for the observed association between the gas exchange proxies and ASD.