Renal pelvic dilation !??

As above really, a scan yesterday picked up on one of my baby boys kidneys being dilated more than normal. I'm 17 weeks along, this was a private gender scan so not a great deal was explained to me apart from not to worry too much and it will be checked again at 20 weeks and then monitored depending on the outcome of that scan.... of course I've been on Google and scared myself silly!!!!! Do any expectant mums or mum's of babies have any experience of this??