Maternal age and prevalence of isolated congenital heart defects in an urban area of the United States.

Although maternal age has been associated with a number of birth defects in several reports, the literature on the association of maternal age with isolated congenital heart defect (CHD) phenotypes has been limited. We evaluated CHD prevalence based on a cohort of 5,289 infants and fetuses with isolated CHDs born during the period 1968-2005 and ascertained by the Metropolitan Atlanta Congenital Defects Program (MACDP) among residents of five central counties in Atlanta. For our denominator, we obtained information on births to residents of the same counties from vital records (n = 1,301,143). We calculated prevalence ratios for 23 CHD phenotypes by several maternal age categories, using the group 25-29 years of age as a reference group. We used Poisson regression models to estimate adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs), controlling for maternal race, infant sex, and birth cohort. A maternal age of 35 years or older was associated with an increased prevalence for several CHD phenotypes: laterality defects (aPR = 2.06; CI 1.22-3.48), all conotruncal defects (aPR = 1.30; CI 1.03-1.65), and specifically for dextro-transposition of the great arteries (aPR = 1.65; CI 1.10-2.48), coarctation of the aorta (aPR = 1.54; CI 1.10-2.16), ventricular septal defects (aPR = 1.20; CI 1.06-1.36), and atrial septal defects (aPR = 1.36; CI 1.05-1.77). Our findings suggest that the birth prevalence of specific isolated CHDs varies with maternal age. Further studies are warranted to corroborate these observations, taking into account potential confounding by known modifiable risk factors.