Antenatal screening for Down's syndrome: where are we and where next?

Abstract

The ability to identify Down's syndrome at a time in gestation when choices about termination can be made dates from the 1970s. Initially, the only available screening test was a question—the woman was asked her age. The likelihood of Down's syndrome increases as the pregnant woman's age advances.1 In the USA, 35 years of age was adopted as the screening cut-off, and pregnant women above that age were routinely offered diagnostic testing. In the UK the age cut-off varied between 35 and 37 years of age in different regions, depending on the availability of diagnostic resources.