In the absence of prenatal testing, the United States would have experienced a 34 percent increase in the number of Down births between 1989 and 2005, Skotko estimates.
Instead, 15 percent fewer such babies were born during that time, representing a 49 percentage point difference between expected and observed rates, according to Skotko's research.
The difference is attributed to abortions:
An estimated 92 percent of all women who receive a prenatal diagnosis of Down syndrome choose to terminate their pregnancies, according to research reviewed by Dr. Brian Skotko, a pediatric geneticist at Children's Hospital Boston.
Unfortunately, the article doesn't provide any data that would back up the claim. Has there been a study done that shows a drop in the number of Down Syndrome children being born?