UMHS LOGOUniversity of Michigan
Department of Pediatrics

Evidence-Based Pediatrics Web Site

A Single Postnatal Ultrasound is Not Sufficient to Evaluate Prenatal Hydronephrosis


  • In infants who have prenatally diagnosed hydronephrosis, what is the management postnatally and can we rely on our initial postnatal ultrasound to assure us there is no renal pathology, particularly with regard to reflux.

Clinical Bottom Lines

  1. The initial ultrasound may be falsely normal in patients with reflux due to a relative dehydration state of neonates. Therefore a f/u ultrasound and/or a VCUG must be done to f/u at 6 weeks.

Summary of Key Evidence

  1. 20 - 40 % of patients followed with postnatal u/s at 1 -2 days of life were found to have VUR on follow-up. These findings were confirmed by multiple studies looking at f/u of prenatal hydronephrosis.
  2. There exists a large controversy in the literature regarding w/u and management of prenatal hydronephrosis.
  3. Some studies recommend f/u of postnatal normal u/s with f/u u/s and others recommend VCUG
  4. All the studies support the use of prophylaxis with trimethoprim or nitrofurantoin until reflux is ruled out.

Additional Comments

  • List any pertinent issues in the critical appraisal
  • List any key biological mechanisms at issue
  • List key elements of the cost or other consequences of executing the bottom line (such as side-effects or toxicity)


  1. Anderson NG, Abbott GD, Mogridge N, Allan RB, Maling TM, and Wells JE. Vesicoureteric reflux in the newborn: relationship to fetal renal pelvic diameter. Pediatric Nephrol, 1997; 11: 610-616.
  2. Dejter SW and Gibbons MD. The fate of infant kidneys with fetal hydronephrosis but initially normal postnatal sonography. The Journal of Urology; 1989; 142: 661-662.
  3. Dudley JA, Haworth JM, McGraw ME, Frank JD, and Tizard EJ. Clinical relevance and implications of antenatal hydronephrosis. Arch Dis Child, 1997;76: F31 - F34.
  4. Zerin JM, Ritchey ML, and Chang ACH. Incidental vesicoureteral reflux in neonates with antenatally detected hydronephrosis and other renal abnormalities. Pediatric Radiology, 1993;187:157-160..

CAT Author: Karen Brenner, MD

CAT Appraisers: John G. Frohna, MD

Date appraised: September 14, 1998

Last updated June 14, 2003
Department of Pediatrics and Communicable Diseases
© 1998-2002 University of Michigan Health System