The researchers spent three years collecting data from multiple registries and databases in every country in Europe to estimate the number of babies being born with DS and the overall number of people with DS in the population. “People with DS were being counted sporadically, inconsistently, or not at all, depending on the country,” says Brian G. Skotko, MD, MPP, a medical geneticist at MGH and senior author. “But without an accurate estimate, it’s impossible for policymakers and advocacy organizations to determine how many resources and support services are needed for its Down syndrome population.” The researchers applied statistical modeling to create estimates in countries where there were gaps in data. “These data are as close to accurate as possible,” says Skotko. The data are laid out in both the study and an associated fact sheet.
Equally important, however, was for the study to establish a baseline of DS birth rates and pregnancy termination rates ahead of widespread adoption of new noninvasive prenatal screenings (NIPS). The new screening tests can detect the likelihood of a chromosomal condition in a fetus as early as nine weeks of gestation, after which an expectant couple can elect to pursue definitive genetic testing. As NIPS becomes widely available, fewer babies with DS are expected to be born.