Fetal umbilical vein varix: antenatal diagnosis and perinatal outcomes

Fetal intra-abdominal umbilical vein varix (FIUVV) is an uncommon fetal vascular abnormality characterized by focal dilatation of the extrahepatic intra-abdominal umbilical vein. A 29-year-old gravida 2 para 1 woman with one previous lower-segment caesarean section was diagnosed with an isolated FIUVV at 28 weeks of gestation during routine ultrasonography. The varix measured 12.3 mm and showed normal venous flow without thrombus. First-trimester screening and the detailed anomaly scan were normal. Serial weekly ultrasonography demonstrated progressive enlargement of the varix to 15.2 mm at 34 weeks, with subsequent development of turbulent flow and progressive fetal growth restriction, while umbilical artery, middle cerebral artery, and ductus venosus Doppler indices remained within normal limits. In view of the progressive enlargement, turbulent flow, fetal growth restriction, and previous caesarean delivery, an elective caesarean section was performed at 34 weeks+5 days. A live female neonate weighing 2295 g was delivered and had an uneventful neonatal course. This case highlights the importance of confirming FIUVV with color Doppler, assessing for associated fetal abnormalities, monitoring fetal growth and changes in the varix, and individualizing delivery planning when concerning sonographic features develop.