title: Influence of nuchal cord on ductus venosus assessment at 11 to 13 + 6 weeks' gestation.
abstract: OBJECTIVE
  To assess the influence of the presence of nuchal cord (NC) on the evaluation of the fetal ductus venosus flow velocity waveform (DV-FVW).
  
  
  METHODS
  This prospective study included 1174 normal non-selected singleton pregnancies between 11 and 13 + 6 weeks' gestation. We recorded the presence or absence of NC around the fetal neck, and assessed its relationship with the qualitative assessment and quantitative measurement of the DV-FVW.
  
  
  RESULTS
  We observed NC around the fetal neck in 6.73% of cases and detected reversed flow of the a-wave of the DV-FVW in 2.98% of cases. In the group without NC, 21 of 1095 had reversed flow in the DV-FVW (1.9%; 95% CI, 1.28-3.02), whereas in the group with NC, 14 of 79 had reversed flow in the DV-FVW (17.7%; 95% CI, 16.67-40.35). We found a lower pulsatility index in fetuses without NC in comparison to those with NC (P < 0.001). We also found an association between the presence of NC and an increased occurrence of absent and reversed a-wave of the flow velocity waveforms (P < 0.001). On multivariate logistic regression analysis, a much higher occurrence of reversed DV-FVW a-wave was detected in fetuses with NC and smaller crown-rump length, and a much higher occurrence of absent DV-FVW a-wave was found in fetuses with NC and a higher maternal body mass index.
  
  
  CONCLUSIONS
  The presence of NC modifies the sonographic findings in the qualitative and quantitative evaluation of the DV-FVW.
authors.affiliation: Fetal Medicine Unit, Department of Obstetrics and Gynecology, Hospital Universitario Materno-Infantil de Canarias, Las Palmas de Gran Canaria, Spain. walterplasencia@mac.com
authors.forename: W
authors.initials: W
authors.lastname: Plasencia
authors.forename: P
authors.initials: P
authors.lastname: Lopez
authors.forename: M
authors.initials: M
authors.lastname: Esparza
authors.forename: R
authors.initials: R
authors.lastname: Garcia
authors.forename: M A
authors.initials: MA
authors.lastname: Barber
authors.forename: J A
authors.initials: JA
authors.lastname: Garcia
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005865:Gestational Age; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D017078:Laser-Doppler Flowmetry; D053589:Nuchal Cord / Q000000981:diagnostic imaging* / Q000196:embryology; D011247:Pregnancy; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000502:physiology; D016216:Ultrasonography, Prenatal