Hi @MumToBe2002 sorry for my late reply, I just saw this email in my junk mail! Congrats on your baby, I totally understand how nerve-wracking it is, even without the added stress of a possible medical issue.
I'm not aware that I had raised blood sugar at any time in my pregnancy, it wasn't ever mentioned when I had any blood or urine tests. Have you been referred to a fetal medicine doctor to look into it? In terms of it 'going wrong', we were told that sometimes these things just happen, very often with kidneys, and there is no underlying reason or anything you did or didn't do, it's just completely random.
My daughter is doing really well now, she is 3 and her unilateral kidney has caused her no issues so far. She hasn't had any infections and we just make sure she keeps well hydrated. She hasn't needed any regular blood sugar or blood pressure monitoring, we just see a kidney paediatrician once a year and they do an ultrasound scan of her kidney to make sure it's growing nicely (it has grown larger to do the job of two kidneys which seems incredible to me). She also gets a yearly blood test to check her kidney function and so far no issues.
I'll never forget what our paediatrician said to us when we first met her- 'don't worry, these kinds of kidney problems won't stop your baby becoming the prime minister!'. It's exactly what we needed to hear at that time- and my daughter seems to have the tenacity and sass required to be PM right now!
I really hope this is in some way reassuring, whilst acknowledging that every baby's circumstances are different. Please look after yourself and surround yourself with supportive people so that you can enjoy your pregnancy as much as possible- feel free to message me in the future if you need to :)