TSH during pregnancy should be <1. It should be tested at every trimester.
TSH should be between 1 and 2. Tested every trimester because level can and will change.
Make sure you get everything checked out. I'm dealing with the same problem. Not to scare you, but I just experienced my third miscarriage last night, which is what brought me to this forum in the first place. My first was 10.5 weeks, second at 5 weeks, and yesterdays was at 8 weeks. It turns out my TSH was at 44. The OB said that there is a very good chance that my hypothyroid is what is causing me to continually miscarry. I've heard lots of stories of people having perfectly healthy babies after dx. Just make sure you keep on top of it, and if you're not comfortable with how things are going... make the doctors make you comfortable. Afterall, you are paying them for a service, and you deserve to have good service! I wish you the best of luck!
She needs to see an endocrinologist. I was hyperthyroid during pregnancy and wasn't treated for the first 10 weeks and my baby at 9 months now is very healthy. I had to see my endo once a month. Don't stress.