Fetal umbilical vein varix: sonographic appearance and postnatal outcome.

We describe five cases of dilation or varix of the umbilical portion of the left portal vein appearing as a fetal intra-abdominal cyst. Doppler or color flow examination, or both, indicated umbilical venous flow within the cystic area in each case. Only one fetus exhibited transient cardiomegaly, which resolved before birth. This fetus was the only one discovered to have the varix as early as the second trimester. All five infants were delivered at term without sequelae.