Postnatal evaluation of infants with an abnormal antenatal renal sonogram.

Objective: Antenatally detected renal abnormalities are frequently encountered. Recommended postnatal evaluation of these infants has evolved to minimize invasive testing while maximizing detection of significant abnormalities.

Results: There is a low rate of detectable renal abnormalities in infants with a normal postnatal sonogram at 4-6 weeks of age. Routine prophylactic antibiotics are not indicated in infants with isolated antenatal hydronephrosis. Infants with a multicystic dysplastic kidney and a normal contralateral kidney on renal ultrasound do not require further evaluation. Parents of these children should be counseled on symptoms of urinary tract infections to allow prompt diagnosis.

Conclusions: All infants with abnormalities on antenatal sonogram should undergo postnatal evaluation with a sonogram after birth and at 4-6 weeks of age. Further evaluation can be safely limited when the postnatal sonogram is normal at 6 weeks of age.