Antenatal renal pelvis dilatation emphasizing vesicoureteric reflux: two-year follow-up of minor postnatal dilatation

Abstract

Aim: To describe the occurrence of foetal renal pelvis dilatation in an unselected population of pregnancies and to describe the clinical course in a subgroup of infants with minor renal pelvis dilatation (RPD). Methods: During 1996–1999 the foetuses of 17850 consecutive pregnant women were scanned with ultrasonography (USG) in the 16th–19th gestational week and later in the pregnancy when indicated. RPD was defined as anterior–posterior pelvic diameter ≤5mm. After birth all infants were examined with USG twice. If any postnatal USG showed RPD ≤10mm, extended radiological investigation was performed. Infants with pelvis dilatation <10 mm and no calyceal or ureteric dilatation were not investigated further and antibiotic prophylaxis was discontinued. The children were followed up at 2 y of age. Results: 109 foetuses (0.6%) with RPD were identified. Postnatally, 94/109 were available for follow-up: 43 had postnatal dilatation ≤10 mm and were investigated and treated according to clinical routine, while 51 had dilatation < 10 mm and were followed up after they had reached at least 2 y of age. No case of pyelonephritis was recorded. USG in 48/51 children was normal. Conclusion: The data indicate that infants with minor RPD do not constitute a risk group for renal morbidity and thus do not need antibiotic prophylaxis and extensive radiological examination.