Denmark's Down Syndrome Births Halved By Screening
Chorionic villus samplings and amniocentesis rates also saw steep decline
MONDAY, Dec. 1 (HealthDay News) -- Since Denmark introduced national combined risk assessment for Down syndrome in 2004, the number of infants born with Down syndrome has dropped by half, according to research published Nov. 27 in BMJ Online First.
Charlotte K. Ekelund, of Copenhagen University Hospital in Copenhagen, Denmark, and colleagues analyzed data from 65,000 pregnancies a year from 2000 through 2007 to find out what changes resulted from screening in 2005 and 2006. Screening, conducted during the first trimester, entailed a risk assessment based on maternal age, nuchal translucency scanning and a test for serum free β human chorionic gonadotrophin and pregnancy associated plasma protein A.
There was a drop in the number of infants born with Down syndrome each year, from 55 to 65 between 2000 and 2004, to 31 in 2005 and 32 in 2006, and whereas in 2000 there were 7,524 amniocenteses and chorionic villus samplings, by 2006 this had dropped to 3,510, the researchers found. Detection rates for 2005 and 2006 were 86 percent and 93 percent, respectively, while the false positive rates were 3.9 percent and 3.3 percent, respectively, the data revealed.
"Even before full implementation of the policy for combined risk assessment during the first trimester in Denmark, the number of infants born with Down syndrome decreased by about 50 percent and the number of cases diagnosed prenatally increased by around 30 percent," the authors write.