Ethnic differences in the impact of advanced maternal age on birth prevalence of Down syndrome

Objectives. This study explored whether ethnic differences in the impact of advanced maternal age on the risk of Down syndrome might reflect differenc es in use of prenatal diagnostic technologies. Methods. Maternal age-specific adds of Down syndrome and amniocentesis use were compared among African Americans, Mexican Americans, and non-Hispanic Whites via birth data for the years 1989 to 1991. Results. The odds ratio and population attributable risk of Down syndrome d ue to maternal age of 35 years or older were highest for Mexican Americans, intermediate for African Americans, and lowest for non-Hispanic Whites. Conclusions. Advanced maternal age has a greater impact on the risk of Down syndrome for African American and, particularly. Mexican American women th an far non-Hispanic White women. This difference in impact might reflect lo wer availability or Use of prenatal diagnostic technologies.