Umbilical Vein Varix

Umbilical vein varix is focal dilatation of the umbilical vein, either inside the fetal abdomen (intra-abdominal) or in the free cord (extra-abdominal). The intra-abdominal type is defined by a vein diameter above 9 mm or 1.5 times the diameter of the intrahepatic portion of the vein, and is the commoner form. It matters because the dilated vein can thrombose or rupture, and is linked with fetal anomalies and a risk of stillbirth.

• Risk factors: chromosomal abnormality, fetal anomaly, maternal diabetes, cord abnormality.
• Isolated intra-abdominal varix has a good outlook.
• Extra-abdominal varix is rarer and has higher risk of thrombosis and fetal death.

Women have no symptoms, and the finding comes from the mid pregnancy scan. Reduced fetal movements or a tracing change suggest complications.

• Found at routine anomaly scan.
• No maternal signs.
• Differential diagnosis: cord cyst, hepatic vein dilatation, persistent right umbilical vein, ductus venosus anomaly, cord haematoma, haemangioma.
• Complications: thrombosis, rupture, fetal heart failure, growth restriction, stillbirth, preterm birth, aneuploidy.

The approach is a detailed anomaly scan with Doppler and karyotype when other findings exist.

• Ultrasound: cystic dilatation of the intra-abdominal umbilical vein with turbulent venous flow on colour Doppler; measure the diameter and the ratio to the intrahepatic vein; extra-abdominal varix seen as a cystic swelling in the cord.
• Detailed anomaly scan and fetal echocardiography; umbilical artery Doppler; growth scans.
• Amniocentesis for karyotype and microarray if other anomalies or a large varix are present.
• Maternal glucose test and blood pressure.

The principle is surveillance for thrombosis, growth restriction and fetal compromise, with delivery at 36 to 37 weeks.

• Supportive: reassure for an isolated intra-abdominal varix; daily fetal movement counts; teach to attend for reduced movements; birth in a unit with neonatal care.
• Pharmacological: betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks and 6 days if preterm delivery is planned; insulin or metformin 500 mg oral with meals increased to 1 g 12-hourly (maximum 2.5 g daily) for diabetes; enoxaparin 40 mg subcutaneous daily with aspirin 150 mg oral at night if thrombosis is found and thrombophilia is confirmed; oxytocin 10 IU IM at birth.
• Procedures: scans with Doppler every 2 weeks from diagnosis (weekly for a large varix) with cardiotocography twice weekly from 32 weeks; delivery at 36 to 37 weeks for isolated intra-abdominal varix, 34 to 36 weeks for extra-abdominal varix or growth restriction, earlier for abnormal tracing or thrombosis; induction or caesarean section on obstetric grounds.
• Red flags: reduced fetal movements, new thrombosis in the varix, abnormal Doppler, falling growth centile, abnormal tracing.
• Follow-up: newborn examination and abdominal ultrasound; genetic counselling if aneuploidy or syndrome is found.