Hashimoto’s thyroiditis, also known as chronic lymphocytic thyroiditis, is an autoimmune disease that is more common in women. For women who are preparing for pregnancy with Hashimoto’s thyroiditis, it is generally recommended that thyroid function tests be completed prior to pregnancy because Hashimoto’s thyroiditis may be combined with hyperthyroidism early on and hypothyroidism may occur as the disease progresses. If you have hyperthyroidism before pregnancy, you will need to correct it first. If you have hypothyroidism before pregnancy, you should be given levothyroxine sodium tablets as replacement therapy to correct the symptoms of hypothyroidism before you become pregnant, and you should be followed closely during pregnancy. For people with normal thyroid function before pregnancy, due to the higher demand for thyroxine during pregnancy, it may lead to insufficient thyroid secretion function, so thyroid function tests need to be perfected every month in the first trimester. If they are all normal, it is fine to recheck thyroid function every three months thereafter.