Angela,
Graves’ disease should be treated during pregnancy, for the sake of the baby–being mildly hyper very slightly increases your risk of miscarriage, and there is also the slight risk that the baby will be born temporarily hyper. However, my endo says that it’s much safer for the baby if you’re a little hyper than if you’re a little hypo (I am also four months pregnant, but my Graves’ disease–which was brought on, I believe, by the birth of my last child–is in PTU-induced remission). My own mother had three children while she had undiagnosed GD (and no miscarriages). I’m one of the three, and we’re fine except that I have GD now–don’t know if it’s just an inherited propensity, or it’s because she was hyper while carrying me. Anyway, be aggressive with your doctors–it’s fine to insist that they address your questions throughly. –Abigail