ESPN 50th Annual Meeting

ESPN 2017

Antenatal Renal Pelvis Dilatation: Determining Risk and Prognostic Factors with Postnatal Significance: Update 2009-2013


As awareness and techniques in antenatal screening advance, detection of foetal anomalies is increasing . Little evidence has been accumulated to determine the importance of antenatal detection of renal pelvis dilatation (RPD) and its association with pathology postnatally. We retrospectively audited all infants born from 2009 to 2013 with RPD and followed their postnatal course in an aim to determine critical RPD dimensions and the importance of associated risk factors.

Material and methods:

We collected data retrospectively on all patients identified by the obstetric ultrasound department as having RPD antenatally in a tertiary neonatal unit with approx. 6,500 births a year. The data was compared to and reflected upon the RPD guideline used across Scotland for identifying infants with significant RPD antenatally and their postnatal management. The data was statistically analysed to determine the risk factors and prognostic factors in outcome of RPD detected antenatally.


In five years 107 patients were identified as having RPD. 77 patients were male and 30 female (2.6:1). 73 identified as high risk and 34 low risk. Of the high risk patients 53 continued to be high risk, with 18 requiring surgery and 8 had UTI. Those that became low risk did not require surgery or UTI. One that did not attend the follow up scan required surgery and had a UTI. Of the low risk patients 11 became high risk with 4 requiring surgery and 5 having breakthrough UTI. Those that continued to be low risk did not require surgery with one UTI. One that did not attend follow up had 1 UTI. In total 24 required surgery, 11 female, 13 male. 37% of females required surgery compared to 17% of males referred. The females had 1 or two risk factors each, however of the boys 4 had one risk factor and 2 had no risk factors, 1 of which did not have high risk RPD dimensions. 15 patients had a breakthrough UTI despite trimethoprim prophylaxis. 1 patient had a UTI not on prophylaxis, however this infant had RPD >15mm. 59 referred to nephrology.


Risk factors and RPD >15mm were the strongest indicator for development of significant RPD requiring surgery or resulting in symptomatic UTI. High risk patients who became low risk at second remained at risk of UTI and surgery. Low risk patients who became high risk became at risk of surgery and UTI. Those who continued to be low risk did not require surgery. Incidence of breakthrough UTI whilst on prophylaxis reflects the need for a high index of suspicion of UTI in a child with RPD. The guideline reflects infants who are at risk of ongoing renal and urology problems postnatally and highlights the importance of follow up in all patients.