In a study comparing maternal age-specific risk rates of Down syndrome by race, Hispanics and whites were the only groups with rates that differed significantly from each other. Hispanics showed higher rates at maternal ages under 40 years (Bishop 1997). Hispanics tend to keep conceiving babies with Down syndrome due to the age of their pregnancies. It was mentioned before that at age 40, the probabilities increase to 1 in 100. The overall reduction in live births with Down syndrome in 1989–1991 that could be attributed to prenatal diagnosis and elective abortion of affected fetuses was 25.8%, with 49.1% of it being observed at pregnancies at 35 years. In 1990–1991, Hispanics showed having the lowest overall reduction which was of (10.0%), while whites had the highest reduction of (46.3%) (Bishop 1997).
Recent advances in surgery for the treatment of congenital heart defects have greatly enhanced the survival of children with Down syndrome. However, despite this enhancement in life expectancy, the ability of children with Down syndrome to reach their full developmental potential may be reduced by disorders of the ear, nose, and throat (Mitchell 2003). This study consisted of 29 children with Down syndrome. Eighteen of the children were Hispanic, five non-Hispanic white, five Native American, and one Asian (Mitchell 2003).
There are three main risk factors for the birth of a Down syndrome infant: elevated maternal age, structurally abnormal 21 chromosome or containing extra material, and the birth of a previous offspring showing signs leading to Down syndrome. In a study, all Down syndrome cases were reported to the Women’s Hospital of the Los Angeles County during a 15 year period from 1974 to 1988, resulting in most Down syndrome births occurring to those of Mexican ancestry and a small proportion from Central America (Hook 1999).