Mummy2one, I have no advice on the fetal side of renal pelvis dilatation but my DS does have the condition. It was initially picked up when he contracting an UTI not long after being discharged from SCN and was readmitted due to the severity of the UTI.

His left renal pelvis measures 3.9mm and right 1.6mm. The measurement and UTI were initial flags that he may have renal reflux or a blockage but tests confirmed that this was not the case. His paediatrician is not at all concerned as the measurement is not more than 10mm. He does have an u/s every 6 months to confirm that there is no increase in size. I have been advised that a decrease in size is expected (in the majority of cases) as the issue usually resolves itself with time.

Hun, I know it's difficult not to worry but bear in mind the majority of cases do resolve themselves in utero or shortly after birth and there is treatment if reflux or blockage is found to be the cause.

Sending H&H vibes to you & bub.