What is the preferred treatment for Graves' disease during pregnancy?

The preferred treatment for Graves' disease during pregnancy is propylthiouracil (PTU) because it has a better safety profile for use in pregnant women compared to other antithyroid medications. PTU is effective at inhibiting the synthesis of thyroid hormones, which helps manage hyperthyroidism caused by Graves' disease.

PTU is particularly favorable during the first trimester of pregnancy because it has a lower risk of causing potential harm to the developing fetus compared to methimazole (Tapazole), which is generally avoided during this critical period due to its association with congenital malformations when used in early pregnancy. PTU is well-studied and has been used safely in pregnancy for many years.

As the pregnancy progresses into the second and third trimesters, the use of methimazole may be considered if the risk of hyperthyroid symptoms outweighs the risks associated with it, but PTU remains the go-to option especially in the first trimester.

Levothyroxine is not used to treat Graves' disease; instead, it is used to treat hypothyroidism. Radioactive iodine is contraindicated during pregnancy due to its potential to harm the fetal thyroid gland and is not an appropriate choice for managing Graves' disease in pregnant patients.