title: Screening for aneuploidy in the first trimester by assessment of blood flow in the ductus venosus.
abstract: OBJECTIVE
  To assess the role of ductus venosus Doppler assessment in screening for fetal aneuploidy in pregnancies at 11-14 weeks of gestation.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  A tertiary referral fetal medicine unit.
  
  
  METHODS
  Two hundred fifty-six consecutive pregnancies between 11 and 14 weeks of gestation referred to our unit.
  
  
  METHODS
  Nuchal translucency was measured and colour Doppler imaging was used to assess normal (forward) or abnormal (absence/reversed) ductus venosus flow during atrial contraction.
  
  
  METHODS
  Fetal karyotype, structural abnormalities and pregnancy outcomes.
  
  
  RESULTS
  The nuchal translucency measurement was > or = 95th centile in 90 (35.2%) pregnancies, and 123 (48.0%) had a nuchal translucency-related risk of > or = 1:300. There were 46 chromosomally abnormal pregnancies and six euploid pregnancies with adverse outcome. The prevalence of abnormal ductus venosus Doppler waveforms in normal pregnancies was 4.49% (95% CI 1.76-8.76%). The sensitivities of abnormal nuchal translucency measurement alone, ductus venosus velocimetry alone or nuchal translucency and ductus venosus combined for Down's Syndrome were 80.4%, 58.7% and 93.5%, respectively. The likelihood ratios for aneuploidy with abnormal nuchal translucency measurement alone, ductus venosus velocimetry alone or nuchal translucency and ductus venosus combined were 3.33, 9.83 and 3.48, respectively.
  
  
  CONCLUSIONS
  There is clear association between abnormal flow in the ductus venosus and fetal aneuploidy. The use of ductus venosus velocimetry in combination with nuchal translucency is better than either test alone, since it increases the sensitivity in the detection of Down's Syndrome to 94% and decreases the likelihood ratio of a negative test to 0.08.
authors.affiliation: Academic Department of Obstetrics and Gynaecology, St George's Hospital Medical School, London, UK.
authors.forename: Eleni
authors.initials: E
authors.lastname: Mavrides
authors.forename: Shanthi
authors.initials: S
authors.lastname: Sairam
authors.forename: Brian
authors.initials: B
authors.lastname: Hollis
authors.forename: Baskaran
authors.initials: B
authors.lastname: Thilaganathan
mesh_terms: D000328:Adult; D000782:Aneuploidy; D001783:Blood Flow Velocity; D005260:Female; D005333:Fetus / Q000098:blood supply; D006801:Humans; D007621:Karyotyping; D008099:Liver / Q000098:blood supply* / Q000196:embryology; D008423:Maternal Age; D008875:Middle Aged; D009333:Neck / Q000196:embryology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods; D014471:Umbilical Veins / Q000196:embryology*; D014682:Vena Cava, Inferior / Q000196:embryology*