title: Screening for Down syndrome using first-trimester combined screening followed by second-trimester ultrasound examination in an unselected population.
abstract: OBJECTIVE
  Recent studies have reported the efficacy of first-trimester combined screening for Down syndrome based on maternal age, serum markers (human chorionic gonadotropin, pregnancy-associated plasma protein A), and ultrasound measurement of fetal nuchal translucency. However, those do not incorporate the value of the widely accepted routine 20-22 weeks' anomaly scan.
  
  
  METHODS
  We carried out a multicenter, interventional study in the unselected population of a single health authority in order to assess the performance of first-trimester combined screening, followed by routine second trimester ultrasound examination and/or screening by maternal serum markers (free beta-hCG and alpha-fetoprotein measurement or total hCG, alpha-fetoprotein, and unconjugated estriol measurement) when incidentally performed. Detection and screen positive rates were estimated using a correction method for nonverified issues. A cost analysis was also performed.
  
  
  RESULTS
  During the study period, 14,934 women were included. Fifty-one cases of Down syndrome were observed, giving a prevalence of 3.4 per 1000 pregnancies. Of these, 46 were diagnosed through first (n = 41) or second (n = 5) trimester screening. Among the 5 screen-negative Down syndrome cases, all were diagnosed postnatally after an uneventful pregnancy. Detection and screen positive rates of first-trimester combined screening were 79.6% and 2.7%, respectively. These features reached 89.7%, and 4.2%, respectively, when combined with second-trimester ultrasound screening. The average cost of the full screening procedure was 108 euros (120 dollars) per woman and the cost per diagnosed Down syndrome pregnancy was 7,118 euros (7909 dollars).
  
  
  CONCLUSIONS
  Our findings suggest that 1 pragmatic interventional 2-step approach using first-trimester combined screening followed by second-trimester detailed ultrasound examination is a suitable and acceptable option for Down syndrome screening in pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Reproductive Biology and Cytogenetics, Poissy-Saint Germain Hospital, University Versailles-St Quentin, Poissy, France. prozenberg@chi-poissy-st-germain.fr
authors.forename: Patrick
authors.initials: P
authors.lastname: Rozenberg
authors.forename: Laurence
authors.initials: L
authors.lastname: Bussières
authors.forename: Sylvie
authors.initials: S
authors.lastname: Chevret
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Bernard
authors.forename: Lydia
authors.initials: L
authors.lastname: Malagrida
authors.forename: Howard
authors.initials: H
authors.lastname: Cuckle
authors.forename: Chantal
authors.initials: C
authors.lastname: Chabry
authors.forename: Isabelle
authors.initials: I
authors.lastname: Durand-Zaleski
authors.forename: Laurent
authors.initials: L
authors.lastname: Bidat
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lacroix
authors.forename: Max
authors.initials: M
authors.lastname: Moulis
authors.forename: Marc
authors.initials: M
authors.lastname: Roger
authors.forename: Marie Christine
authors.initials: MC
authors.lastname: Jacquemot
authors.forename: Jean Philippe
authors.initials: JP
authors.lastname: Bault
authors.forename: Philippe
authors.initials: P
authors.lastname: Boukobza
authors.forename: Patrick
authors.initials: P
authors.lastname: Boccara
authors.forename: Francois
authors.initials: F
authors.lastname: Vialard
authors.forename: Yves
authors.initials: Y
authors.lastname: Giudicelli
authors.forename: Yves
authors.initials: Y
authors.lastname: Ville
mesh_terms: D000328:Adult; D004314:Down Syndrome / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D017048:Health Care Costs; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000191:economics / Q000592:standards; D015995:Prevalence; D016216:Ultrasonography, Prenatal / Q000191:economics / Q000592:standards