[Ductus venosus agenesis]

Congenital absence of the ductus venosus is a rare anomaly in the fetus. The aim of our study was to evaluate the clinical and ultrasonographic features and outcome of the fetuses with ductus venosus agenesis.

We describe 12 cases in the period between 1992 and 2004. The umbilical vein drained either into the right atrium directly (2 cases) or by the coronary sinus (1 case), or in the inferior vena cava (5 cases), or in the azygos vein (1 case), or in the portal vein (3 cases). Our data where analyzed with the cases published in the literature. Two groups of anastomoses where defined on the basis of the hemodynamic consequences: the group of extrahepatic anastomoses (53 cases) and the group of intrahepatic anastomoses (22 cases).

In the group of extra hepatic anastomoses, cardiomegaly was the most common antenatal finding (39%), while in the intra hepatic group hydrops fetalis occurred most frequently (23%). Malformation rate was high in both groups (56% and 45%) and chromosomal anomalies where present in 9% of cases.

Careful assessment of the umbilical venous return and the ductus venosus should be a part of examination of every fetus with cardiomegaly, polyhydramnios, ascites or hydrops. In case of absence of the ductus venosus a referral scan, a fetal echocardiography and a karyotype should be performed.