Researchers have developed a complex computer program that could lead to a safer and more accurate prenatal test for disorders such as Down syndrome. Combining blood and ultrasound tests from the first and second trimesters of a pregnancy, the computer program can identify Down syndrome with only a one per cent chance of a false positive result. This means that the program could potentially identify 85 per cent of Down syndrome cases when standard screening detects 46 per cent. Amniocentisis, one currently available method of prenatal testing, comes with a one per cent risk of miscarriage.

The new technique could reduce the number of women who have to undergo amniocentisis as well as improving detection rates. However, experts warn that a larger trial is needed before any change in clinical practice. The research is reported in the current issue of The New England Journal of Medicine.