Ultrasound enhances noninvasive Down syndrome tests

HOUSTON -- (November 23, 2009) -- The addition of a “genetic sonogram” maximizes the accuracy of non-invasive testing for Down syndrome, said a Baylor College of Medicine researcher who was lead author of a landmark study in the current issue of Obstetrics and Gynecology.

“We wanted to be able to definitively describe the detection and accuracy of noninvasive prenatal screening for the detection of Down syndrome,” said Dr. Kjersti Aagaard-Tillery, assistant professor of obstetrics and gynecology at BCM and the corresponding author of the report. “Using our data generated in the most comprehensive study performed to date (the FaSTER trial), we demonstrated that the addition of a genetic sonogram to all modes of screening in pregnancy allows for optimal noninvasive prenatal detection of Down syndrome.” (FaSTER stands for First and Second Trimester Evaluation of Risk.)
Early tests

Noninvasive screening for Down syndrome (as well as the other major fetal genetic or chromosomal abnormalities in the developing baby) involves a specific early ultrasound and series of tests for biochemicals in the mother’s blood at particular times during pregnancy. Depending on the institution and clinic, tests are done during the first and/or second trimesters of pregnancy. Optimally, noninvasive screening also includes that a preliminary ultrasound to detect nuchal translucency takes place late in the first trimester. The test measures the clear or translucent space in the tissue at the back of the fetus’ neck. If there is an abnormality, fluid will accumulate in the back of the neck making the nuchal fold area larger.

source: Baylor College of Medicine