title: MULTISCAN--a Scandinavian multicenter second trimester obstetric ultrasound and serum screening study.
abstract: OBJECTIVE
  To study the detection rates of second trimester ultrasound screening for neural tube defects (NTD), abdominal wall defects (AWD) and Down's syndrome (DS) in low risk populations at tertiary centers, and to compare the ultrasound screening detection rates with those that were obtainable by biochemical serum screening (double test: alpha-fetoprotein/human chorion gonadotrophin/age test).
  
  
  METHODS
  Prospective multicenter study with a three year inclusion period: 1/1/1989-31/12/1991.
  
  
  METHODS
  27,844 low-risk women at 18-34 years of age who had a second trimester ultrasound screening examination. Of these, 10,264 also had a serum test.
  
  
  METHODS
  An ultrasound malformation scan and a serum test were carried out at 17-19 weeks of gestation. Risk calculations regarding DS were based on alpha-fetoprotein, human chorion gonadotrophin and maternal age; performed retrospectively for the first two years.
  
  
  RESULTS
  In total 73 cases were identified in the study population: NTD (n=34), AWD (n=7) and DS (n=32). The detection rates, (%, with 95% confidence interval) for ultrasound screening were: NTD: 79.4 (62.1-91.3); AWD: 85.7 (42.1-99.6); DS: 6.3 (0.8-20.8). In the subgroup of women who had both tests, the detection rates for ultrasound screening vs double test were: NTD: 62.5 (24.5-91.5) vs 75.0 (34.9-96.8); AWD: 66.7 (9.4-99.2) vs 100 (29.2-100.0); DS: 7.7 (0.2-36.0) vs 46.2 (19.2-74.9). The false positive rates (%) for ultrasound screening vs double test were: NTD: 0.01/3.3; AWD: 0.01/3.3; DS: 0.1/4.0.
  
  
  CONCLUSIONS
  Second trimester ultrasound screening in a low risk population gave a low detection rate for fetal DS (6.3%) and an acceptable detection rate for NTD (79.4%) and AWD (85.7%). In the subgroup of women who had both tests, serum screening performed better than ultrasound as applied in the present study, especially regarding DS.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: F S
authors.initials: FS
authors.lastname: Jørgensen
authors.forename: L
authors.initials: L
authors.lastname: Valentin
authors.forename: K A
authors.initials: KA
authors.lastname: Salvesen
authors.forename: C
authors.initials: C
authors.lastname: Jørgensen
authors.forename: F R
authors.initials: FR
authors.lastname: Jensen
authors.forename: J
authors.initials: J
authors.lastname: Bang
authors.forename: S H
authors.initials: SH
authors.lastname: Eik-Nes
authors.forename: M
authors.initials: M
authors.lastname: Madsen
authors.forename: K
authors.initials: K
authors.lastname: Marsal
authors.forename: P H
authors.initials: PH
authors.lastname: Persson
authors.forename: J
authors.initials: J
authors.lastname: Philip
authors.forename: J W
authors.initials: JW
authors.lastname: Bogstad
authors.forename: B
authors.initials: B
authors.lastname: Nørgaard-Pedersen
mesh_terms: D000009:Abdominal Muscles / Q000002:abnormalities; D000293:Adolescent; D006063:Chorionic Gonadotropin / Q000097:blood*; D000013:Congenital Abnormalities / Q000175:diagnosis*; D004314:Down Syndrome / Q000175:diagnosis; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis; D006801:Humans; D009436:Neural Tube Defects / Q000175:diagnosis; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D012307:Risk Factors; D016216:Ultrasonography, Prenatal; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins