Improved Accuracy of DNA Testing for Down Syndrome Inside the Womb

All mothers would want to know for sure that their unborn baby is healthy and will come into the world without any complications. As much as technology has advanced, there are still some conditions that are difficult, or even impossible, to detect inside the womb, and Down syndrome definitely makes the cut.

A more recent study, however, might bring some new assurances to younger mothers with low-risk, who can take a Roche blood test that determines whether or not their unborn baby suffers from Down syndrome.

Dr. Mary Norton from the University of California, San Francisco said this test should be taken with a grain of salt, because it doesn’t detect everything and it shouldn’t be considered a clear diagnostic.

This study used data collected by previous researches on how to perform fetal DNA tests. They involve getting DNA fragments from the placenta that circulates the mother’s blood. This is truly an accurate method of detecting Down syndrome, and it also tests for two other chromosomal abnormalities that can occur in pregnancies of high-risk women (older than 35 years).

The average age of the almost 16,000 women participating in the study was 30, and what they did was to put Roche’s Harmony test in contrast with the standard prenatal examination for Down syndrome. Both techniques give diagnosis based on biomarkers found in the blood and on fetal ultrasound results.

The Roche test was able to diagnose 38 Down syndrome cases, in contrast with the standard examination, which detected 30 cases. The new test had also a much lower rate of false positive cases (0.06 percent), a significant decrease from the standard screening’s rate – 5.4 percent.

As much as 500 pregnant women participating in the study had trouble, as the fetal DNA in the mother’s blood was not enough for performing the new test. With additional testing, Norton’s team found that 2.7 percent of the fetuses presented chromosomal defects, including some left undetected by the new fetal DNA method.

Unfortunately, the test is still pending U.S. FDA approval outside clinical trials, and those who did get a chance to participate should not rely on this diagnosis alone. What is really important for anyone undergoing a procedure with the new DNA test is that physicians strongly discourage the decision of pregnancy termination because of the results of such screenings.

Second and third opinions about the baby’s health are recommended, as well as taking the well-regulated tests; pre-approved studies are not to be used as definite sources for termination decisions.

Image Source: Noah’s Dad

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Ryan Harris

Ryan has started his career as a web developer and designer before joining us. He enjoys the creativity work and loves experimenting with various techniques in both print and web. He covers the social media, technology and gadgets updates.