title: First trimester biochemical screening for trisomy 21: the role of free beta-hCG and pregnancy associated plasma protein.
authors.forename: L
authors.initials: L
authors.lastname: Breimer
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D010446:Peptide Fragments / Q000097:blood*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011296:Prenatal Diagnosis
chemical_list: D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments; D011266:Pregnancy-Associated Plasma Protein-A