Maternal age and non-chromosomal birth defects, Atlanta--1968-2000: teenager or thirty-something, who is at risk?

OBJECTIVE

This investigation explored the association between maternal age and non-chromosomal birth defects to assess any increased risk associated with maternal age.

METHODS

Birth defect cases were ascertained by the Metropolitan Atlanta Congenital Defects Program (MACDP), denominator information was obtained using birth certificate data. Infants with any chromosomal diagnosis were excluded. Effect estimates were calculated using 5-year maternal age categories with 25-29 years as the referent. Multiple logistic regression was used to adjust for maternal race, parity, infant sex, and birth year.

RESULTS

A total of 1,050,616 singleton infants, born after > or = 20 weeks gestation in the five counties of metropolitan Atlanta from 1968 through 2000 who did not have a chromosomal abnormality and whose mother was 14 to 40 years old, were included in the analyses, 32,816 of them were identified with birth defects by the MACDP. Young maternal age (14-19 years) was associated with anencephaly (OR = 1.81, 95% CI = 1.30-2.52), hydrocephaly without neural tube defect (OR = 1.56, 95% CI = 1.23-1.96), all ear defects (OR = 1.28, 95% CI = 1.10-1.49), cleft lip (OR = 1.88, 95% CI = 1.30-2.73), female genital defects (OR = 1.57, 95% CI = 1.12-2.19), hydronephrosis (OR = 1.42, 95% CI = 1.11-1.82), polydactyly (OR = 1.29, 95% CI = 1.09-1.52), omphalocele (OR = 2.08, 95% CI = 1.39-3.12), and gastroschisis (OR = 7.18, 95% CI = 4.39-11.75). Advanced maternal age (35-40 years) was associated with all heart defects (OR = 1.12, 95% CI = 1.03-1.22), tricuspid atresia (OR = 1.24, 95% CI = 1.02-1.50), right outflow tract defects (OR = 1.28, 95% CI = 1.10-1.49), hypospadias 2nd degree or higher (OR = 1.85, 95% CI = 1.33-2.58), male genital defects excluding hypospadias (OR = 1.25, 95% CI = 1.08-1.45) and craniosynostosis (OR = 1.65, 95% CI = 1.18-2.30).

CONCLUSIONS

Young and advanced maternal ages are associated with different types of birth defects. Underlying causes for these associations are not clear.