Other Treatments. Some, but not all, obs prefer that women not be on thyroid-blocking medicines during pregnancy. If one is used, ptu (propylthiouracil) is usually preferred over methimazole. Surgery should not complicate future pregnancies, but has other complications, and is usually not the best choice.
It's complicated. The most common treatment for graves' with radioactive iodine requires that you not become pregnant for 6-12 months afterwards to prevent harm to the baby. Once a person is well established on thyroid hormone, a pregnancy should not be any more difficult than usual. Anyone taking thyroid hormone who becomes pregnant should speak with their doctor about a dose change.