Non-invasive Chromosomal Examination of Trisomy Study

The purpose of this blinded, multi-center, prospective, case-controlled study is to compare the Ariosa Harmony™ Prenatal Test for trisomy 21 detection with a standard first-trimester prenatal screening test consisting of serum screening (PAPP-A,free beta-hCG \[β-hCG\] or total hCG) and a nuchal translucency (NT) measurement (i.e. combined first trimester screening) in a general screened population. The performance characteristics of these two test modalities will be assessed relative to the clinical reference standard of genetic analysis of the fetus or phenotypic characterization and genetic analysis of the newborn.