Two healthy babies miscarry following testing for Down's Syndrome for every three foetuses diagnosed with the condition in the womb, according to new research.

Two healthy babies miscarry following testing for Down's Syndrome for every three foetuses diagnosed with the condition in the womb, according to new research.

The ratio was condemned as "completely unacceptable" by one of Britain's leading foetal health experts, who called for the speedy introduction of better screening of mothers-to-be to reduce reliance on the invasive tests which are blamed for miscarriages.

According to figures compiled by the Down Syndrome Education International charity, some 660 cases of the condition are detected by antenatal testing in England and Wales each year, most of them leading to abortions. But 400 healthy babies are lost following the tests.

DSEI chief executive Frank Buckley said: "Around 400 babies without Down's Syndrome being lost in the process of preventing the birth of 660 babies with Down's Syndrome - that's around two babies without for every three babies with.

"I think that's a shocking ratio."

Around 600,000 women a year in England and Wales are offered screening for Down's, often by ultrasound scan. However, this does not detect all cases of the condition and inevitably results in a sizeable number of "false positives".