Because PTU can also affect the baby's thyroid gland, it is very important that pregnant women be monitored closely with examinations and blood tests so that the PTU dose can be adjusted. In rare cases when a pregnant woman has a serious PTU side effect, surgery to remove the thyroid gland is the only alternative. Although radioactive iodine is very effective for other patients, it should never be given during pregnancy because the baby's thyroid gland could be damaged. Because treating hyperthyroidism during pregnancy can be tricky, it is usually best for women who plan to have children soon to have their thyroid condition permanently cured. Antithyroid medication alone may not be the best approach because hyperthyroidism often returns when medication is stopped.
Radioactive iodine is the most widely recommended permanent treatment.
It is concentrated by thyroid cells and damages them with little radiation to the rest of the body. The only common side effect of radioactive iodine treatment is underactivity of the thyroid gland, which can easily and safely treated with levothyroxine. There is no evidence that radioactive iodine treatment of hyperthyroidism interferes with a woman's future chances of becoming pregnant and delivering a healthy baby. Surgery is less commonly recommended because it is less convenient and uncomfortable, and rarely can have complications. One of every twenty women develops thyroid inflammation within a few months after delivery of their baby, a condition called postpartum thyroiditis .