Propylthio usually refers to propylthiouracil, and pregnant women should take propylthiouracil under doctor’s supervision if they have a combination of hyperthyroidism. Propylthiouracil is an antithyroid medication used for hyperthyroidism. Although it is not advisable for propylthiouracil to cross the placental barrier into the fetus, pregnant women should use it with caution to avoid adverse effects on the fetus. In non-essential cases, propylthiouracil is not recommended during pregnancy. Therefore, for women suffering from hyperthyroidism, it is best to control the condition under the guidance of a doctor and prepare for pregnancy and get pregnant after the condition has stabilized. If you are already pregnant and at the same time find that the symptoms of hyperthyroidism cannot be well controlled without medication, you can take propylthiouracil during pregnancy, but you need to use the medication under the guidance of a doctor. It is recommended to pay more attention during pregnancy and avoid unauthorized use of medication to avoid adverse effects on the fetus.