According to researchers, it appears that a DNA-based blood test is more effective to detect possible Down syndrome in unborn children as compared to other screening methods for the genetic disorder.

The researchers said that the test displayed perfect accuracy in a clinical trial by detecting Down syndrome in all 38 women whose kids had inherited the disorder. According to authors of a study standard screening methods only detected Down syndrome in 30 of the 38 pregnant mothers.

As per the researchers, fetal DNA circulating freely in a pregnant woman's bloodstream has been analyzed. The researchers said that higher quantities of fetal DNA in blood of women is a sign that her unborn child suffers from Down syndrome.

"It is clearly a better test than what we're currently using. If one is looking at screening specifically for Down syndrome, there's no question this test is better for that purpose", said study lead author Dr. Mary Norton, a professor and vice chair of clinical and translational genetics at the University of California, San Francisco.

Mothers have been warned by experts that they must follow up any positive result with an invasive diagnostic test like amniocentesis before making any decisions about their pregnancy. The researchers said that they compared a positive result in a cell-free DNA test to a positive cancer screen.

According to the experts, Down syndrome takes place when a baby has an extra copy of chromosome 21 in its DNA. So far, screening for Down syndrome included an earlier blood test and an ultrasound, according to the US Centers for Disease Control and Prevention.

In the new clinical trial, the researchers compared this screening method to the cell-free DNA screening test. Previous studies concentrated on older women assumed to be at higher risk for birth defects and this trial focused on about 15,000 women with an average age of 31. It was found by the researchers that the cell-free DNA test had a much lower false-positive rate as compared standard screening.