title: Ductus venosus Doppler at 11 to 13 weeks of gestation in the prediction of outcome in twin pregnancies.
abstract: OBJECTIVE
  To examine the independent contribution of abnormal flow in the ductus venosus at 11 to 13 weeks of gestation in the prediction of adverse pregnancy outcome in relation to chorionicity.
  
  
  METHODS
  This was a prospective study in 516 dichorionic and 179 monochorionic twin pregnancies in which the fetal ductus venosus flow was assessed at 11 0/7 to 13 6/7 weeks of gestation. The prevalence of reversed a-wave in the fetal ductus venosus was compared between monochorionic and dichorionic pregnancies and between those with and without pregnancy complications. Comparisons between each of the pregnancy outcomes and the normal outcome group and between monochorionic and dichorionic pregnancies were made using the Mann-Whitney U-test for continuous variables and the chi2 test and Fisher exact test for categorical variables.
  
  
  RESULTS
  The prevalence of reversed a-wave in at least one of the fetuses was significantly higher in monochorionic than in dichorionic pregnancies (18.4% compared with 8.3%, P<.001) and in pregnancies complicated by miscarriage (28.6%, P=.005), fetal aneuploidy (70.0%, P<.001), and twin-twin transfusion syndrome (38.5%, P<.001) compared with the pregnancies with two healthy live births (7.7%). Pregnancy outcome was normal in 33 of the 43 (76.7%) dichorionic and in 14 of the 33 (42.4%) monochorionic twins with reversed a-wave in at least one of the fetuses.
  
  
  CONCLUSIONS
  In twins, reversed a-wave in the ductus venosus at 11 to 13 weeks of gestation is associated with increased risk for aneuploidies, miscarriage, and development of severe twin-twin transfusion syndrome. However, in about 75% of dichorionic twins and 40% of monochorionic twins with reversed a-wave, the pregnancy outcome is normal.
  
  
  METHODS
  II.
authors.affiliation: From the Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, United Kingdom.
authors.forename: Nerea
authors.initials: N
authors.lastname: Maiz
authors.forename: Ismini
authors.initials: I
authors.lastname: Staboulidou
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Leal
authors.forename: Ryoko
authors.initials: R
authors.lastname: Minekawa
authors.forename: Kypros H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000026:Abortion, Habitual; D000328:Adult; D000782:Aneuploidy; D001783:Blood Flow Velocity; D005260:Female; D005315:Fetal Diseases / Q000453:epidemiology; D046689:Fetal Mortality; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D005333:Fetus / Q000098:blood supply*; D005865:Gestational Age; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000209:etiology; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D011673:Pulsatile Flow; D012039:Regional Blood Flow / Q000502:physiology; D012680:Sensitivity and Specificity; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology*