In response to multiformity in the management of antenatally detected renal pelvis dilatation (RPD) in the UK and the absence of any clear NICE guidelines, we carried out a national audit in 2005/2006 with some interesting results.

The audit was designed as a questionnaire which was mailed during the second half of 2005 to consultants nationwide who were responsible for the follow-up and management of antenatally detected RPD in British neonatal units. The response rate was 39.9% (95 responses).

The questionnaire mainly requested information about the local definition of RPD, antibiotic prophylaxis and antenatal and postnatal investigations.

At 16–20 weeks of gestation, about 70% of units regarded a transverse renal pelvis measurement of ⩾5 mm as indicating RPD. However, at 30–34 weeks of gestation only 40% of units regarded ⩾5 mm as suggestive of RPD, with 30% choosing ⩾7 mm and 20% ⩾10 mm (fig 1).

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Figure 1 Renal pelvis measurements considered indicative of antenatal renal pelvis dilatation at (A) 16–20 weeks’ and (B) 30–34 weeks’ gestation.

After a diagnosis of RPD, most units arranged postnatal ultrasound scans (USS) with variable urgency and frequency depending on local guidelines and the clinical setting (fig 2).

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Figure 2 Timing of postnatal scans (n = 95) “Other (1)” indicates that a scan was carried out at a single other time point, while ”Other (mult)” indicates that scans were carried out at more than one time point.

It was noticeable that about 10% of units do not use micturating cystourethrograms (MCUG) postnatally at all when following up patients with antenatally detected RPD. Nevertheless, 49 units stated clearly that they use MCUG in addition to USS if indicated.

Concerning the postnatal use of prophylactic antibiotics, which so far lacks any proper evidence, again most units practise a uniform approach and give prophylactic doses of antibiotics starting on day 1.

Regarding the follow-up of babies after discharge, it seems general practitioners (GPs) still play a major role with 57 units involving GPs in the long-term care of babies with RPD.

In conclusion, the antenatal detection of renal pelvis dilatation is still a new and highly debated area with no national guidelines for the management and follow-up of babies, a situation which results in diverse practice throughout the UK. In addition, it has been suggested that current guidelines may possibly result in over-treatment of normal babies.

We highly recommend the continued auditing of current practice against available guidelines and review of the presentation of febrile urinary tract infection or other complications in children below 2 years of age, as a marker for the failure of existing guidelines.

And finally, we propose carrying out a national randomised controlled trial of the follow-up of mild to moderate antenatal RPD, an condition which still requires more research.

Acknowledgements

We thank Dr Hester Yorke and the Audit Department, Queen Mary’s Hospital for Children, Carshalton, Surrey, UK.