For every 660 detections of the condition, the tests result in 400 miscarriages of healthy babies, the latest data revealed. "Around two babies without Down's syndrome are being lost in the process of preventing the birth of three with Down's," said Down Syndrome Education International chief Frank Buckley.
The charity has called on the government to reassess offering screening for pregnant women.
"The screening is to offer woman information so they can make informed decisions," the Department of Health stressed. "To ensure that screening is both effective and safe for all women, a quality assurance system has been set up."