High antithyroid peroxidase antibodies in pregnant women may be caused by some kind of autoimmune thyroid disease, such as Hashimoto’s thyroiditis and Graves’ disease. Specific treatments vary depending on the condition. For example, if a pregnant woman has high antithyroid peroxidase antibodies along with a thyroid-stimulating hormone (TSH) level greater than 2.5 mU/L and less than 4.0 mU/L, levothyroxine treatment needs to be considered. 1. If there is a decrease in TSH and an increase in serum free triiodothyronine and free thyroxine at the same time as an increase in antithyroid peroxidase antibody, oral antithyroid medication, such as methimazole or propylthiouracil, may be required under medical supervision. 2. If a pregnant woman with high anti-thyroid peroxidase antibodies has subclinical hypothyroidism in pregnancy, the treatment is related to the TSH level. If the TSH is less than 2.5 mU/L and more than 0.1 mU/L, regular monitoring of the TSH will be sufficient; if the TSH is more than 2.5 mU/L and less than 4.0 mU/L, levothyroxine should be considered as a treatment to avoid affecting the fetus’s physical and intellectual development. Intellectual development of the fetus. Pregnant women with high anti-thyroid peroxidase antibodies should go to the hospital in time and be treated under the guidance of a doctor.