Radioactive iodine treatments and antithyroid drugs are usually effective in slowing down thyroid hormone output, but in some cases surgery is the best approach for Graves' disease. Your doctor may recommend subtotal thyroidectomy -- a relatively safe and simple procedure in which most of the thyroid gland is removed -- if you develop the disorder before or during pregnancy. She may also suggest it if you're reluctant or unable to do radioactive treatment or are allergic to antithyroid medication.