*   Ultrasound Division, ASL Roma B, Rome, Italy.
** Ultrasound Division, Ceprano Hospital, Ceprano, Italy.

Introduction

This anomaly represents a variation of the umbilical venous anatomy with obliteration of the left umbilical vein and persistence of the right umbilical vein. Right umbilical vein is normally obliterated at the sixth week of the embryonic life.

Ultrasound diagnosis

The sonographic diagnosis of the persistent right umbilical vein is simple. It can be done at the transverse section of the fetal abdomen:

• umbilical vein curves towards the stomach

• fetal gallbladder is located medially to the umbilical vein, it is between the stomach and the umbilical vein.

The above mentioned findings are the indication for a detailed fetal ultrasound and echocardiography examination. In case, the persistent right umbilical vein is connected to the portal system and other anomalies are ruled out, the outcome is generally favorable.

Case report

We present a case of the persistent right umbilical vein. A 28- year-old woman G1P0 was presented to our department at 22+3 weeks. Her first trimester ultrasound performed at 12+4 weeks, ouside of our department, reported to be normal (NT 1.6 mm). A persistent right umbilical vein was detected. Ductus venosus was present. There were no other anomalies detected during the ultrasound examination. Fetal echocardiography was performed at 23 weeks and showed no abnormalities.

The patient was scanned again at 34 weeks for evaluation of the fetal growth. Surprisingly, the gallbladder was not visible at this examination. The fetal growth and amniotic fluid were slightly above the 75^th percentile. Gestational diabetes was diagnosed and the patient followed a low-carbohydrates diet.

Patient delivered spontaneusly at 40+5 weeks a healthy female neonate, 3910 grams with Apgar scores 9/10 (5th/10th minute respectively). No additional findings were detected on the neonate.

Images 1,2: Image 1 shows the stomach (red) and the gallbladder (green) which is located in the midline. Image 2 shows the gallbladder in the midline and the four chamber view of the heart.

Images 3,4: Image 3 shows a right umbilical vein curving left, towards stomach. Image 4 shows a right umbilical vein which is laterally to the gallbladder.  

Images 5,6: Images show stomach (red) located on the left and right umbilical vein (blue) which curves towards the stomach.

Images 7,8: Color Doppler imaging demonstrating the persistent right umbilical vein, note the curve towards the stomach.

Images 9,10: Image 9 shows a Doppler of the right umbilical vein and ductus venosus. Image 10 shows a sagittal view of the fetal abdomen.

Images 11,12: Images show a characteristic Doppler waveform of the ductus venosus.

References

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