Blood Tests on Pregnant Moms Can Reveal Down Syndrome

Scientists in Europe report they were able to diagnose Down syndrome prenatally by giving a simple blood test to pregnant women, an approach that might one day help them avoid the more extensive procedure used now to detect the condition.

The preliminary report published online Sunday in the journal Nature Medicine is the latest of several recent studies that suggest scientists can spot Down syndrome through fetal DNA that has been shed into the mother's bloodstream.

Down syndrome, which results in cognitive delays, is caused by having an extra copy of a particular chromosome. Currently, pregnant women get blood tests and ultrasound to find out if the fetus is at risk for Down syndrome. For a firm diagnosis, doctors take a sample of amniotic fluid or the placenta.

Those sampling procedures involve a small risk of miscarriage. A reliable diagnostic blood test also could give an answer earlier than the standard tests.

Several research teams have published studies suggesting that analyzing the mother's blood can detect Down syndrome in a fetus. There's no commercial test available yet, but at least one company hopes to introduce one in the U.S. within about a year.

In the latest report, scientists in Cyprus, Greece and Britain said that in a blind test, they correctly identified 14 Down syndrome cases and 26 normal fetuses.

They said a bigger study is needed to confirm the usefulness of their approach.