I had hyperthyroidism diagnosed when I was pregnant, (8 years ago now). I had no problem carrying her to term however I was closely monitored though out my pregnancy. I was on medication, tablets that I had to take twice a day, they weren't recommended for pregnancy however my Ob said the risks were higher for the baby by not taking them.
I had scans and full blood works done every two weeks. When my DD was born we had to stay in the hospital for 2 weeks as they did daily observations on her, checking her heart rate and bloods etc. When I left the hospital I was given open admission to the children's ward for her which meant I could take her straight there without having to go to a GP or A&E. She was absolutely fine though, no problems with her.