Down's Syndrome Test May Require Too Much Patience

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All prospective parents would prefer to avoid putting an unborn child at risk with amniocentesis, the current test for Down's syndrome, but would they wait the month for a verdict that a new, safer test involves? That's the question being debated following the release of a new study, published Thursday in the New England Journal of Medicine, in which researchers developed a computer program that can collate the results of two non-invasive procedures carried out a month apart to more accurately establish the presence of Down's syndrome. Although neither a first trimester blood test and ultrasound nor a second trimester blood test offers a definitive answer, a team of British researchers found that by correlating the results with their program they were able to identify 85 percent of Down's syndrome cases with only a 1 percent false positive rate. Amniocentesis provides a definitive answer, but the procedure involves withdrawing fluid from the fetal sac using a needle, which triggers miscarriages in 1 percent of such procedures.

"This method would potentially give a more accurate reading of which women should be advised to undergo amniocentesis," says TIME medical correspondent Christine Gorman. "But among women who might abort rather than give birth to a Down's syndrome baby, if a first-trimester test contains a warning sign, most would be unlikely to want to go through the agony of waiting until the second trimester for a definitive answer. This study contains some interesting clinical observations, but unfortunately what it really shows is that there’s still no conclusive non-invasive test for Down's syndrome."