WHAT IS THE NATURAL HISTORY OF ANTENATALLY DETECTED RENAL PELVIS DILATATION?
Ellen Dyer1, Rebecca Hawkes2, 1University of Cambridge, 2Cambridge University Hospitals
Background:
The detection of renal pelvis dilation (RPD), defined as a renal pelvis above 7mm, is frequently identified during the routine anatomy scan at 20 weeks. RPD is not one of the fetal anomaly screening programme auditable conditions; however, it is best practice to follow up RPD later in pregnancy and postnatally. Knowledge of the natural history of RPD helps to guide antenatal counselling.
Aim:
To examine the follow-up and outcome of antenatally detected RPD.
Method:
The Astraia database at a tertiary referral centre was searched for cases of RPD between January 2022 and December 2024. 101 cases were identified; after removing duplicates, other renal conditions or extra-renal anomalies, the sample included 71 cases. The Astraia reports at 20 weeks, 32 weeks and postnatal scans were reviewed independently by an obstetric and paediatric sonographer. Predefined demographics and clinical information were obtained from the electronic patient record and analysed in Excel and STATA.
Results:
61/71 cases were followed up at 32 weeks of gestation. 26 (42.6%) had resolved by 32 weeks. 39 cases were followed up postnatally, and a further 17 resolved (including one case without antenatal follow-up). This equated to 43/62 (70.5%) of cases resolving either antenatally or postnatally. Ten babies had renal anomalies that persisted postnatally. These included 6 with reflux, 1 pelvic-ureteric junction obstruction (PUJO), 1 reflux with PUJO and 2 with persistent RPD of unknown cause. Inconsistency in follow-up of RPDs was observed with 12 (46.1%) of the antenatally resolved RPDs also scanned postnatally.
Conclusion:
The majority of isolated RPDs were resolved (70.5%). This provides useful information for the antenatal counselling of parents. The inconsistencies identified during this audit highlight the need for local agreement on RPD follow-up and management.