title: Reference values of ductus venosus blood flow velocities and waveform indices from 10 to 20 weeks of gestation.
abstract: OBJECTIVE
  Our objective was to establish reference values for ductus venosus flow velocities during ventricular systole (S wave) and diastole (D wave), the lowest forward velocity during atrial contraction (A wave) and different calculated indices [(S-A)/D), (S-A)/Vmean, (S-A)/S, S/A, S/D)].
  
  
  METHODS
  Ductus venosus flow velocity waveforms were obtained from 329 singleton pregnancies at 10-20 weeks of gestation by pulsed-wave color Doppler. Reference values were constructed by means of a quadratic regression model after logarithmic transformation of original data.
  
  
  RESULTS
  A significant increase in blood flow velocity during atrial contraction [A-wave, (3.5 cm/s to 9.9 cm/s and 12.9 cm/s to 66.3 cm/s respectively, 5-95% centile)], during ventricular systole [S-wave, (19.2 cm/s to 30.1 cm/s and 45.1 cm/s to 84.9 cm/s respectively, 5-95% centile)] and during early ventricular diastole [D-wave, (15.7 cm/s to 26.1 cm/s and 37.9 cm/s to 77.9 cm/s respectively, 5-95% centile)]. The venous indices values decreased with increasing gestational age. In 3 of 329 fetuses (0.91%) a reversed flow during atrial contraction was seen.
  
  
  CONCLUSIONS
  Assessment of ductus venosus blood flow velocities during first and second trimester is feasible by means of color Doppler flow. The reference ranges and calculated velocities established in this study may be utilized in studies dealing with the role of ductus venosus blood flow in chromosomal abnormal fetuses, fetuses with congenital heart disease or fetal myocardial insufficiency of hypoxic origin.
authors.affiliation: Division of Prenatal Medicine, Department of Obstetrics and Gynecology, Medical University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. raxtfliedner@hotmail.com
authors.forename: R
authors.initials: R
authors.lastname: Axt-Fliedner
authors.forename: S
authors.initials: S
authors.lastname: Diler
authors.forename: T
authors.initials: T
authors.lastname: Georg
authors.forename: M
authors.initials: M
authors.lastname: Friedrich
authors.forename: K
authors.initials: K
authors.lastname: Diedrich
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D004373:Ductus Arteriosus / Q000196:embryology / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000098:blood supply*; D005865:Gestational Age; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011673:Pulsatile Flow; D012016:Reference Values; D015203:Reproducibility of Results; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal / Q000592:standards*