title: Effects of gestation dating in Down's screening.
authors.forename: D J
authors.initials: DJ
authors.lastname: Worthington
mesh_terms: D006063:Chorionic Gonadotropin / Q000032:analysis; D004314:Down Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D015233:Models, Statistical; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012307:Risk Factors; D014463:Ultrasonography; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins