The effective management of Graves' disease (GD) during pregnancy is crucial for maternal and neonatal well-being. Conventional treatment of GD during pregnancy includes antithyroid drugs (ATDs) and surgery, ideally during the second trimester. We report a 27-year-old woman with GD and we present the course of GD during her three consecutive pregnancies. During the first pregnancy, thyrotoxicosis was successfully treated with low doses of antithyroid drugs; in the second pregnancy, thyrotoxicosis was only controlled at the third trimester; while in the third pregnancy, our patient presented with treatment-resistant thyrotoxicosis, which was finally managed with corticosteroids in adjunction with ATDs. Although hyperthyroid, the patient maintained her fertility. Resistance to ATD is a rare condition and in our case was adequately controlled with corticosteroids.