Failure of kidneys to form

No kidneys in renal fossa or anywhere else in fetus

Adrenal glands are present and large, can mimic kidneys

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  Have ice cream sandwich appearance with hypoechoic cortex and hyperechoic medulla

  
  
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  Flattened, lying down appearance; lacks normal tricorn hat configuration

Absent renal arteries

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  Best evaluated with coronal aorta color Doppler view

No fluid-filled bladder

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  Best evaluated with axial pelvis color Doppler view showing no bladder between umbilical arteries

No amniotic fluid in 2nd/3rd trimester (anhydramnios)

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  Normal or low-normal fluid might be seen before 16 wk

Associated findings

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  Pulmonary hypoplasia from oligohydramnios

  
  
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  Limb deformities: Club feet, contractures

  
  
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  Facial anomalies: Micrognathia, low-set ears

Other causes of severe oligohydramnios

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  Premature rupture of membranes

  
  
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  Severe growth restriction

  
  
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  Bilateral renal anomaly

Bilateral agenesis is considered lethal anomaly

Associated with aneuploidy and genetic syndromes

Saline infusion may help with fetal anatomy evaluation

Set color Doppler gain carefully so as not to “light up” lumbar arteries, which may mimic renal arteries

Look for pelvic kidney when kidneys not seen in renal fossa

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  Renal artery may come off iliac artery