Kimmy, does the doctor know what it is exactly? There are various illness of the thyroid-- one of my nieces(I have 7 nieces) has hyperthyroid and just had a baby last year....... she has been on medication and the baby is fine-- she's even breast feeding. She was diagnosed with "Graves Disease" and as soon as the baby is weened she will have to take that radioactive iodine to destroy her thyroid. Her mom-- my sister, had to do the very same thing in her early twenties also.
Almost all the females in my family have some type of thyroid disease-- wonder if it runs in your family as well?

I hope your daughter will get good care and that everything will be fine.
Thinking of you and your family-

mandy