Study Finds More Accurate Down Syndrome Test

By Liz Townsend

A study published in the Lancet November 16 asserts that Down syndrome can be identified in 11- to 14-week-old unborn babies by checking for the absence of the nasal bone.

The authors of the study, led by Prof. Kypros Nicolaides of London's Harris Birthright Research Centre for Fetal Medicine, checked if 701 unborn babies between the ages of 11 and 14 weeks had a nasal bone. Of the 59 babies later found to have Down syndrome, 73% did not have a nasal bone. Only three (0.5%) of the chromosomally "normal" babies lacked the bone, according to BBC News. The researchers claim that the nasal bone test could reduce the number of miscarriages caused by amniocentesis, an invasive procedure often used to confirm a Down syndrome diagnosis, BBC News reported. The rate of false positives could decrease from 5% to 1% if the nasal bone test is used in combination with other non-invasive methods, the authors claim.

Even if some babies are saved by a diagnosis that they do not have Down syndrome, many will be aborted if the test shows they have the syndrome. The Daily Mail reported that four out of five pregnant women in Britain ask for their babies to be screened for Down syndrome, and 95% of those diagnosed as "high risk" for a Down's baby have an abortion.

The study authors consider early detection of Down syndrome and a subsequent abortion to be an advantage of the test. "These benefits include, for some, an early diagnosis with consequently safer and less traumatic therapeutic abortion, and, for most, an earlier reassurance," Prof. Harold Cuckle of Leeds University wrote in the Lancet.