ultrasound of fetal venous system: normal anatomy, variation and anomalies: a review article

The fetal venous system begins developing around the sixth week of gestation, with three paired veins: the umbilical, vitelline, and cardinal veins. these veins are essential for transporting blood from the placenta to the heart. as the liver matures, connections between the liver and these veins form a complex venous system. disruptions in this process can lead to various fetal venous anomalies, arising from abnormalities in the formation or regression of these veins. common anomalies include ductus venosus agenesis, persistent right umbilical vein, umbilical vein varix, agenesis of the portal system, and ivc interruptions. ductus venosus agenesis can cause compensatory blood flow changes, while a persistent right umbilical vein occurs when the left vein regresses. umbilical vein varix is a dilation of the umbilical vein, and agenesis of the portal system disrupts normal liver blood flow. ivc interruptions affect systemic venous return to the heart. diagnosing these anomalies requires detailed ultrasound evaluation, including doppler studies, and prenatal monitoring to assess potential complications and guide appropriate clinical management. in evaluating complex communication pathways, the first step is to examine how that structure is organized. the categorized segmentation of the venous system leads to a wider horizon of vision and higher perception. in this pictorial essay article, the fetal venous system and its anomalies are classified according to their primary origin. special attention to depicting normal anatomy and anomalies using color schematic images and real two-dimensional and color ultrasound images together play an important role in promoting spatial perception and simplifying the categorized approach to fetal venous system anomalies.