Due to the increasing number of questions from patients with abnormal thyroid function during pregnancy, this small scientific article is written for your reference. Every woman may want to have her thyroid function checked when she is ready to become pregnant in order to detect subclinical hypothyroidism or true hypothyroidism in time to ensure the health of the fetus. It is especially important for women who already know they have Hashimoto’s thyroiditis or who have a family history of thyroid disease to undergo this test before pregnancy. Then, in patients with subclinical hypothyroidism, there are already data showing an increased risk of adverse pregnancy outcomes and neurointellectual developmental impairment in the offspring. In patients with TPOAB-positive subclinical hypothyroidism, the need for intervention with Eugenol is even greater. For those patients with subclinical hypothyroidism with TSH greater than 10 mIU/L, they should always be treated with Eugenol anyway. For both clinical and subclinical hypothyroid patients, the TSH index needs to be controlled within 2.5mIU/L before pregnancy. After pregnancy, it is recommended that the above patients should have their thyroid function checked at least once a month (preferably once every two weeks) during the first trimester of pregnancy and increase or decrease the dosage of Eugenol under the guidance of the doctor