The Columbia University Medical Center is reporting on some pretty impressive and very important results from a large trial that looked at the effectiveness of screening for Down’s syndrome.
38,000+ pregnant women underwent the Nicolaides nuchal translucency ultrasound test (essentially, a neck skin thickness measurement in the fetus), and blood tests (pregnancy-associated plasma protein A [PAPP-A], the free beta subunit of human chorionic gonadotropin):
The new screening approach uses a blood test that analyzes the level of a protein and hormone in the mother’s blood, combined with an ultrasound or sonogram picture of the thickness of skin on the back of the baby’s neck (known as the nuchal translucency or NT). Results are available within five days, often before starting the second trimester of pregnancy. This combination approach determines the odds that the baby might have Down syndrome, allowing pregnant women the option of prenatal diagnosis for Down syndrome and other chromosomal abnormalities within the first trimester or pregnancy. The researchers found higher detection – 87 percent – in the first trimester compared to the best second trimester screening method – 81 percent detection. Results with this new combination screening approach in the first trimester are a significant advantage over the current standard screening test.
First-trimester screening was performed on 38,167 patients; 117 were found to have a fetus with Down syndrome. If a positive result is found via screening, the woman is given the option to have the finding confirmed with a diagnostic exam: chorionic villus sampling (CVS) or amniocentesis. Both tests carry risks of complication leading to miscarriage.