Is maternal age a risk factor for mental retardation among children?

The purpose of this study was to determine whether older or very young maternal age at delivery is associated with mental retardation in children. Ten-year-old children with mental retardation (an intelligence quotient of 70 or less) were identified in 1985-1987 from multiple sources in the metropolitan Atlanta, Georgia, area. These children were subdivided into two case groups according to whether they had concomitant developmental disabilities or birth defects affecting the central nervous system (codevelopmental retardation) or did not have such disabilities (isolated retardation). Control children were randomly chosen from the regular education files of the public school systems in the study area. Data on sociodemographic variables were gathered from birth certificates. Children of teenaged mothers were not at increased risk for either form of retardation and children of mothers aged > or =30 years were not at increased risk for isolated retardation, in comparison with children of mothers aged 20-29 years. A markedly elevated risk of codevelopmental retardation was seen among black children of mothers aged > or =30 years that was not attributable to Down syndrome. A modest increase in risk for codevelopmental retardation was observed among white children born to older mothers, but it was entirely due to Down syndrome.