New Study Reports Effective First-Trimester Screening for Down Syndrome
Down syndrome is a disorder that includes a combination of birth defects, such as mental retardation, characteristic facial features, heart defects, and vision and hearing impairments. It is one of the most common genetic birth defects, affecting approximately one in 800 to 1,000 babies. It is generally caused by an extra chromosome, the structures in cells that contain the genetic information (genes).
According to a recently released study, a first-trimester screening test can reliably detect fetuses likely to be born with Down Syndrome, providing women with reliable information much earlier in their pregnancies than current testing permits. The $15 million study, funded by the National Institute of Child Health and Human Development, spanned eight years and involved 38,000 women.
This new screening test uses ultrasound examination, called nuchal translucency, to measure the thickness of the skin on the back of a fetus's neck and a blood test to measure pregnancy-associated protein and hormone levels. Currently, reliable testing for Down Syndrome is limited to chorionic villus sampling and amniocentesis, both of which are somewhat invasive and carry a small risk of miscarriage. The American College of Obstetricians and Gynecologists, which issues influential recommendations for prenatal screening, is expected to update its advice to reflect the study's findings. Click here to read an ABC News report on this study, and here for more information about Down Syndrome in general from the March of Dimes.