Increased risk for developmental disabilities in children who have major birth defects: A population-based study

Objective. We sought to quantify the strength of associations between each of four specific developmental disabilities (DDs) and specific types of maj or birth defects. Methods. We linked data from 2 independent surveillance systems, the Metrop olitan Atlanta Congenital Defects Program and the Metropolitan Atlanta Deve lopmental Disabilities Surveillance Program. Children with major birth defe cts (n=9142; born 1981-1991 in metro Atlanta) and 3- to 10-year-old childre n who were born between 1981 and 1991 in metro Atlanta and identified betwe en 1991 and 1994 as having mental retardation, cerebral palsy, hearing impa irment, or vision impairment (n=3685) were studied. Prevalence ratio (PR), which is the prevalence of a DD in children with 1 or more major birth defe cts divided by the prevalence of the same DD in children without major birt h defects, was measured. Results. Among the 9142 children who were born with a major birth defect, 6 57 (7.2%) had a serious DD compared with 0.9% in children with no major bir th defect, yielding a PR of 8.3 (95% confidence interval: 7.6-9.0). In gene ral, the more severe the DD, the higher was the PR. Birth defects that orig inated in the nervous system and chromosomal defects resulted in the highes t PRs for a subsequent DD. For all other categories of birth defects, PRs w ere lowest when all major birth defects present were confined to a single c ategory (ie, isolated defects). PRs for any DD increased monotonically with the number of coded birth defects per child or the number of different bir th defect categories per child, regardless of the severity of the defect or whether defects of the nervous system, chromosomal defects, or "other synd romes" were counted. Conclusions. These data highlight the possible early prenatal origins of so me DDs and suggest that both the number of coded birth defects present and the number of anatomic systems involved are strongly related to functional outcomes.