Fetal intra-abdominal umbilical vein varix 2022-01-31T04:50:28Z Fetal umbilical vein dilatation Fetal intra-abdominal umbilical vein varix (FIUVV) is defined by the focal dilatation of the fetal umbilical vein between its entry in the abdomen and its ending in the portal system. The dilatation can be defined using one of the following criteria: a portion of intra-abdominal umbilical vein that is at least 50% wider than the non-dilated portion; a dilatation of 9 mm or more, or a dilatation greater than 2 SD above the mean value for gestational age. FIUVV Foetal umbilical vein dilatation Umbilical vein varix