Persistent right umbilical vein

A persistent right umbilical vein (PRUV) is an uncommon vascular anomaly which is often detected in utero.

Epidemiology

The estimated prevalence is ~2 per 1000 births ^1,2.

Pathology

In the normal situation, the right umbilical vein begins to obliterate in the ~4^th week of gestation and disappears by the 7^th week. With a PRUV, the right umbilical vein remains open and the left umbilical vein usually obliterates. A PRUV may also be supernumerary ⁶.

Location

A PRUV can be intra- or extrahepatic. The former is much commoner.

Associations 

Numerous associations have been described (albeit at relatively low rates ^3,9). They are commoner with the extrahepatic type and include:

• single umbilical artery: especially in the extrahepatic type 
• chromosomal anomalies
  • trisomy 18
• Noonan syndrome ⁸
• situs anomalies
  • dextrocardia
• congenital cardiac anomalies
• congenital renal anomalies
• congenital gastrointestinal anomalies
• vertebral anomalies

Radiographic features

Antenatal ultrasound

It is usually detected in the 2^nd to 3^rd trimester. Assessment is usually made in the axial plane and color Doppler is often required. An intrahepatic persistent right umbilical vein may be seen as an umbilical vein abnormally connected to the right portal vein and the fetal gallbladder is positioned medial to the PRUV. 

Treatment and prognosis

When additional anomalies are ruled out, a PRUV in isolation carries a generally favorable outcome ^1,9.

Practical points

If a persistent right umbilical vein is detected, a careful sonographic anatomical survey is generally recommended to rule out more serious congenital malformations ¹⁰.

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