“…In the last ten years, the assessment of the fetal venous system using spectral and color Doppler evolved dramatically. Reference ranges were established for different vessels throughout gestation, focusing on: the inferior vena cava (Rizzo et al, 1992;Hecher et al, 1994), the hepatic veins (Hecher et al, 1994); the ductus venosus (Huisman et al, 1992;Kiserud et al, 1991); and, recently, the pulmonary (Brezinka et al, 1999;Paladini et al, 1997;Better et al, 1996;Laudy et al, 1995); and intracranial veins (Laurichesse-Delmas et al, 1999). The assessment of different Doppler parameters from the systemic veins was introduced into clinical practice in the management of fetuses with severe intrauterine growth retardation or cardiac failure (Reed et al, 1990;Kanzaki and Chiba, 1990;Hecher and Campbell, 1996;Rizzo et al, 1992).…”