title: The umbilical artery pulsatility index in the first trimester: is there an association with increased nuchal translucency or chromosomal abnormality?
abstract: OBJECTIVE
  The aim of this study was to examine the possible association between umbilical artery pulsatility index (PI) at 10-14 weeks of gestation and either increased fetal nuchal translucency (NT) or fetal chromosomal abnormality.
  
  
  METHODS
  This was a prospective study of women undergoing chorionic villus sampling (CVS).
  
  
  METHODS
  A total of 458 women undergoing CVS were studied; in 418 cases the karyotype was normal and in 19 cases fetal trisomy 21 was identified.
  
  
  METHODS
  Data from the women with a normal fetal karyotype and in whom the NT was also normal were used to calculate reference anges for the umbilical artery PI. Associations were sought between umbilical artery PI and increased NT and between the PI and fetal trisomy 21.
  
  
  RESULTS
  We found no association between umbilical artery PI and NT, nor was there a difference in the PI between chromosomally normal pregnancies and those with fetal trisomy 21.
  
  
  CONCLUSIONS
  The results suggest that fetoplacental vascular resistance per se does not contribute to increased NT and that measurement of the umbilical artery PI does not contribute to the first-trimester detection of fetal trisomy 21.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Brown
authors.forename: L
authors.initials: L
authors.lastname: Di Luzio
authors.forename: C
authors.initials: C
authors.lastname: Gomes
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging* / Q000235:genetics; D006801:Humans; D007621:Karyotyping; D009333:Neck / Q000196:embryology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000502:physiology; D012016:Reference Values; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging* / Q000502:physiology