title: Screening for Down syndrome in the first trimester.
abstract: Second-trimester maternal serum screening for Down syndrome is now well established, and permits detection of up to 70% of cases. The disadvantage of this sort of screening is that the timing of maternal blood sampling is relatively late (after 15 weeks). There is an accumulating body of evidence to suggest that in the first trimester concentrations of a number of pregnancy-associated proteins and hormones differ in chromosomally normal and abnormal pregnancies. A first-trimester maternal serum screening test for Down syndrome may therefore be possible. In addition, new methods of screening have recently been described based on ultrasound findings at 11 to 13 weeks of gestation. This review article presents a discussion of published data on the feasibility of first-trimester screening for Down syndrome.
authors: Department of Obstetrics and Gynaecology, Royal London Hospital, UK.
authors: K J
authors: KJ
authors: Powell
authors: J G
authors: JG
authors: Grudzinskas
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis*; D004964:Estriol / Q000097:blood; D005260:Female; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis; D011268:Pregnancy-Specific beta 1-Glycoproteins / Q000032:analysis; D011296:Prenatal Diagnosis; D016216:Ultrasonography, Prenatal; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D006063:Chorionic Gonadotropin; D011268:Pregnancy-Specific beta 1-Glycoproteins; D000509:alpha-Fetoproteins; D011266:Pregnancy-Associated Plasma Protein-A; D004964:Estriol