(454) Fetal sex and the impact on antenatally detected renal pelvis dilation

This was a retrospective chart review of all cases of fetal APRPD diagnosed in singletons prior to 28 weeks over a three year period (2018-2020) in a tertiary care center utilizing the multidisciplinary consensus for classification of urinary tract dilation. The data was assessed to determine fetal sex involvement in diagnosis, concurrent anomalies, laterality and rates of resolution in the third trimester.  

Results: A total of 206 fetuses were diagnosed with APRPD >4 mm prior to 28 weeks of gestation during this study period.  Of these, 132 were singleton gestations, with no other anomalies and with third trimester follow up.  In fetuses with diagnosed with APRPD, males represented a larger percentage than females (73.5% vs 26.5%). Despite sex disparity at diagnosis, resolution rates in the third trimester ( < 7mm) were similar (72.2% males, 74.3% females; p: 0.81).  Both sexes had similar likelihood of bilateral kidney involvement (55.7% males, 48.6% females; p: 0.47) and the maximal dilation at diagnosis was also similar (males 5.6mm +/- 0.12, female 5.56mm +/- 0.22). No differences were found in other anomaly types. 

Conclusion:

While male sex was found to be associated with a higher likelihood of mid-trimester APRPD, there was no difference found between the sexes in rates of resolution, maximal pelvis dilation at diagnosis, or concurrent anomalies.