title: Maternal serum screening for alpha-fetoprotein, unconjugated estriol, and human chorionic gonadotropin between 11 and 15 weeks of pregnancy to detect fetal chromosome abnormalities.
abstract: OBJECTIVE
  The purpose of this prospective study was to assess the value of maternal serum screening between 11 and 15 weeks of gestation to detect fetal Down syndrome.
  
  
  METHODS
  Blood samples were collected on 993 women between 11 and 15 weeks' gestation before amniocentesis. Ninety percent were > or = 35 years old. Samples were coded and assayed for alpha-fetoprotein, unconjugated estriol, and human chorionic gonadotropin. Medians were established at each week between 11 and 15 from 836 normal, singleton pregnancies.
  
  
  RESULTS
  We used a computer-generated cut-off risk for Down syndrome of one in 365 at term; nine of 11 (82%) Down syndrome pregnancies were identified. There were 23% false-positive results in women > or = 35 years old and 6% in those < 35 years.
  
  
  CONCLUSIONS
  These results suggest that maternal serum screening between 11 and 15 weeks may provide an acceptable alternative to screening between 16 and 20 weeks.
authors.affiliation: Department of Pediatrics, University of California, Los Angeles.
authors.forename: B F
authors.initials: BF
authors.lastname: Crandall
authors.forename: F W
authors.initials: FW
authors.lastname: Hanson
authors.forename: S
authors.initials: S
authors.lastname: Keener
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto
authors.forename: W
authors.initials: W
authors.lastname: Miller
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood*; D002869:Chromosome Aberrations / Q000175:diagnosis*; D025063:Chromosome Disorders; D004314:Down Syndrome / Q000175:diagnosis; D004964:Estriol / Q000097:blood*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D012307:Risk Factors; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol