Several definitions in use

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  Focal dilatation of umbilical vein (UV) > 9-mm diameter

  
  
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  Varix diameter 50% > intrahepatic portion of UV

  
  
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  UV diameter > 2 standard deviations above mean for gestational age

Cyst-like space in upper abdomen with venous flow on Doppler

Usually intraabdominal, extrahepatic

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  May be intrahepatic or even in free loops of cord

Cord umbilical vein varix (UVV) is diagnosis of chance, as hard to systematically run length of cord in mobile fetus

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  Rupture of UVV in free loops may → fetal exsanguination

Abdominal cysts (none show internal blood flow)

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  Choledochal cyst

  
  
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  Meconium pseudocyst

  
  
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  Ovarian cyst

  
  
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  Enteric duplication cyst

  
  
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  Urachal cyst

Umbilical cord cysts (flow in surrounding umbilical vessels, not in cyst)

If UVV seen, perform detailed anatomic survey

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  ~ 35% have other anomalies

  
  
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  Cardiovascular, renal most common

Formal fetal echocardiogram as UVV may be 1st manifestation of elevated venous pressures

Monitor for signs of impending hydrops

Monitor varix size, presence of thrombus

Monitor fetal growth

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  Increase surveillance if fetal growth restriction develops