My Daughter Is 33 Weeks Pregnant And Failed The Three

My daughter is 33 weeks pregnant and failed the three hour glucose test. The doctor is going to treat her with a special diet no melds at this time. She was very healthy not over weight has gained 20 pounds no history of our diabetes etc. I'm concerned about her and especially unborn baby. Just how concerned should I be? My daughter is an RN and I don't want to ask too many questions and cause more stress.