Prenatal Features of Omphalocele and Absent Ductus Venosus

Abstract

Absence of the ductus venosus (ADV) is a rare vascular anomaly; however, the advent of color Doppler sonography has facilitated detailed analysis of the fetal venous system, and prenatal diagnosis has been described in the recent literature. 1-16 The ductus venosus is a short vascular channel with a maximum diameter of 2 mm, which connects the intra-abdominal umbilical vein with the inferior vena cava (IVC). Because of its role as a sphincter in the isthmic portion, the ductus venosus regulates the proportion of umbilical vein return, thus protecting the fetus from excessive placental flow. Congenital absence of this narrow vessel leads to lack of this regulation, and subsequent volume overload can place a substantial burden on fetal myocardial performance with the risk of high-output cardiac failure. If the chronic volume overload is severe, cardiomegaly, polyhydramnios, and fluid accumulation such as pleural effusion, ascites, pericardial effusion, and skin edema may occur. Furthermore, ADV is associated with a high incidence of other anomalies. Because of its high incidence of associated anomalies and hydrops fetalis, fetuses with ADV have a high mortality rate. 1-3 The most frequently reported associated anomaly is congenital heart disease. No reports to date have associated ADV with a congenital abdominal wall defect. Here we describe the case of a fetus with omphalocele with extracorporeal liver in association with ADV, which was diagnosed prenatally. The fetus showed polyhydramnios, cardiomegaly, and unilateral pleural effusion as signs of cardiac impairment; however, this condition did not develop throughout the pregnancy, and the neonate survived.