title: Ultrasound dating in first-trimester biochemical screening for Down syndrome.
authors.forename: A
authors.initials: A
authors.lastname: Borrell
authors.forename: M T
authors.initials: MT
authors.lastname: Farré
authors.forename: D
authors.initials: D
authors.lastname: Costa
authors.forename: A
authors.initials: A
authors.lastname: Fortuny
mesh_terms: D000782:Aneuploidy; D002869:Chromosome Aberrations / Q000000981:diagnostic imaging / Q000196:embryology; D025063:Chromosome Disorders; D004314:Down Syndrome / Q000000981:diagnostic imaging* / Q000196:embryology; D005260:Female; D006801:Humans; D007621:Karyotyping; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016216:Ultrasonography, Prenatal