D.B.
I had this same thing with son number two (and posted a very similar question on here one the time). He is 7 months old and was born with minor drama and thriving and doing well. His drama at birth was mostly focused on the fact that I'm type one diabetic and he decided to make his appearance 5 weeks earlier than expected. I quizzed my high risk OB about whether the SUA contributed and he assured me it wasn't.
They will likely do another ultrasound sound to assure that his other vitals are growing normally (I think, according to info I got) because SUA mostly effects the blood flow to the heart and brain, due to being one artery short. They can see how much blood flow is going to these organs on the follow up ultrasound.
I know it sounds SO SCARY and the info on the internet only makes you even more terrified. My OB tried to make sure I stayed as calm as possible and didn't become completely overwhelmed. Most babies born with SUA turn out just fine and have no other medical issues. If you're able to, go to my name and view my previous questions...If I rememeber correctly, I got some REALLY useful info in my responses.
Take a deep breath momma and try to relax okay. It won't do you any good to freak out and contemplate worse case scenarios.