The significance of fetal renal pelvic dilatation as a predictor of postnatal outcome.

Objectives: To define the clinical outcome of fetal renal pelvic dilatation (FRPD) in cohort of infants in United Arab Emirates.

Study Design: Data were collected from all fetuses having FRPD from January 2005 to February 2008. FRPD was graded as normal (<5 mm), mild (5-9 mm), moderate (10-15 mm), and severe (>15 mm).

Results: Data from 80 fetuses with 120 kidneys were studied. Nine resolved antenatally and seven were lost to follow up. Of the remaining 89 FPRD (64 patients), 36% had normal postnatal ultrasound, 22.5% significant uropathy, and 41.5% had isolated hydronephrosis. Pelvi-ureteric junction obstruction was the commonest identified underlying abnormality. Severe FRPD predicted significant postnatal uropathy with a sensitivity of 65% and a specificity of 98.6%. Moderate FRPD increased the sensitivity to 95% but decreased the specificity to 60.9%, mild FPRD was seldom (4%) associated with significant postnatal pathology. Postnatal resolution was significantly (p = 0.01) higher in mild RPD than in the moderate or severe group.

Conclusion: Severe FRPD need comprehensive postnatal assessment. Although moderate FRPD had a high prevalence of uropathy, they rarely needed surgical intervention. Parents could be reassured that RPD of less than 10 mm in the third trimester is unlikely to be associated with significant uropathology.