Fetal hydronephrosis

Hey everyone, I went in for my 20 week ultrasound yesterday and was told we are having a girl! But was also told she has the possibility of slight hydronephrosis. The nurse practitioner I saw (just started a new practice too) was very unhelpful and wouldn't tell me anything... Just referred me to a perinatologist and scared the daylights out of me. Other than this possibility, baby looked great and no other abnormalities were noted.

Anyone gone through this and have any insight? Seems to be more common in boys, so it's strange that it's a possibility in my girl! Any advice and help welcome. I don't see the high risk doctor till next week and am trying to calm myself before then.