title: First-trimester Down syndrome screening.
authors: J N
authors: JN
authors: Macri
authors: F
authors: F
authors: Orlandi
mesh_terms: D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D005820:Genetic Testing; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First