My daughter is 8 days old. On the antenatal ultrasound showed minimal left pelvic pyelectasis of 6.3mm We have had the follow up ultrasound yesterday at a week old. It states the left side, there is mild prominence of the renal pelvis with an AP diameter of about 21mm. There is also mild prominence of the major upper and lower pole major calyces. Part of the renal pelvis appears to be extrarenal in position and this could be a developmental variation. No ureteric dialation seen On the views of the bladder, the bladder outline appears normal. Conclusion Normal size kidneys No abnormalities are seen on the right overall. Mild prominence of the renal pelvis and major calices on the left. Part of the renal pelvis appears to be extrarenal in position ?cause ?developmental variation. Could you please tell me is this serious and does it require immediate medical attention?