Thyroid disorders in pregnancy mainly include hyperthyroidism and hypothyroidism. The incidence of the former is about 1/500, while the incidence of the latter is only 1/5000. The former is most common in Graves’ disease, and the incidence of miscarriage, stillbirth, neonatal death and intrauterine growth retardation increases in untreated or poorly treated cases. Also, hypothyroidism in pregnancy increases the incidence of miscarriage and stillbirth, and if the treatment is not standardized, cretinous babies may be delivered and the incidence of stillbirth increases. We mainly introduce the pharmacological treatment of pregnancy combined with hyperthyroidism and pregnancy combined with hypothyroidism for clinical reference. I. Pharmacological treatment of pregnancy or maternal hyperthyroidism The current treatment measures for hyperthyroidism mainly include antithyroid drugs, surgery and radioactive iodine. However, drug therapy is mostly used for combined hyperthyroidism in pregnancy. Because the fetal thyroid gland has the function of concentrating iodine after 12 weeks of pregnancy, most of the treatment with radioactive iodine during pregnancy will cause congenital hypothyroidism in the fetus, therefore, women who receive 131I treatment should first exclude pregnancy, and if they are pregnant, they should terminate the pregnancy. In contrast, surgical treatment should only be used in pregnant women who have failed to respond to antithyroid medication or who are allergic to antithyroid medication. The main antithyroid drugs are propylthiouracil, methimazole and carbimazole. 1. Propylthiouracil is a pregnancy risk category D. Its action is to block the synthesis of thyroxine in the thyroid gland; and block the conversion of thyroxine to triiodothyronine in peripheral tissues. PTU has a high binding rate to plasma proteins, and compared with methimazole, it is not easy to pass through the placenta and is safer for the fetus, so it is used as the first choice during pregnancy. Whether PTU is teratogenic is controversial because of the high incidence of malformations in newborns of pregnant women with hyperthyroidism. The adverse effects of PTU are skin rash and granulocytopenia. The skin rash is generally not serious, granulocytopenia is a serious complication, during the use of drugs should often check the peripheral blood leukocyte count and classification, when the granulocytopenia or even lack of granulocytes, to immediately stop the drug, and take appropriate treatment measures. 2. Methimazole (Tabazol) is a pregnancy risk category D. Methimazole rarely binds to plasma proteins and easily crosses the placental barrier, with a drug concentration ratio of 0.8:1.09 in cord blood/maternal blood. In addition, there have been reports of fetal malformations caused by methimazole in pregnant women treated with hyperthyroidism, the main malformation being a scalp defect. Therefore, methimazole should be used with caution. 3.Carbimazole (Methimazole) is the risk category D for pregnancy. Carbimazole is converted into methimazole in the body, which is functionally equivalent to methimazole, and its strength is about 10 times higher than PTU. In the past, it was advocated to add thyroid powder to anti-thyroid drugs in order to prevent neonatal hypothyroidism. The reasons are: (1) thyroid powder does not easily pass through the placenta and is not beneficial to the fetus; (2) it does not prevent fetal hypothyroidism but increases the dosage of antithyroid drugs for the mother; (3) it affects the measurement of thyroid function. 5, the application of B-blockers Pregnant women with hyperthyroidism often have tachycardia, and in the past, internists used to use B-blockers to treat tachycardia in patients. However, long-term use of B-blockers can cause intrauterine growth retardation, bradycardia, preterm delivery, neonatal respiratory depression and hypoglycemia, so it is generally not recommended. 6. Treatment of fetal hyperthyroidism Fetal hyperthyroidism is caused by high titers of thyroid-stimulating antibodies (TSAb) in the mother entering the fetus via the placenta. The chance of fetal hyperthyroidism in a pregnant woman with Graves’ disease is 1%, and the clinical manifestation is an unexplained rapid fetal heart rate. The condition should be considered when maternal serum TSAb levels are elevated and ultrasound examination indicates fetal goiter and heart enlargement. The mother can be given methimazole 30-60mg daily and the dose of methimazole should be adjusted according to the fetal heart rate. The mother’s thyroid function should be monitored to determine if supplemental thyroid powder is needed. 7. Application of antithyroid drugs during lactation Antithyroid drugs can enter the breast in small amounts, and PTU is less likely to enter the breast than methimazole. The American Academy of Pediatrics believes that lactating mothers can continue breastfeeding with this product. The drug treatment of pregnancy combined with hypothyroidism is effective in controlling the symptoms of pregnancy combined with hypothyroidism and preventing complications for mother and child by giving a full replacement dose of thyroid powder. The main replacement drugs are levothyroxine and thyroid powder. 1. Levothyroxine is a pregnancy risk category A. It is the levothyroxine isomer of thyroid powder, with long half-life and stable action, and should be the first choice of replacement medication. Active replacement therapy to maintain maternal free triiodothyronine and free thyroxine at normal levels is very important for early fetal brain development. The product rarely passes through the placenta and is generally considered to have no effect on fetal thyroid function. According to relevant data, 554 pregnant women who used this product during the first 3 months of pregnancy did not show a significant increase in the rate of fetal malformation. It is also reported in the literature that intra-amniotic injection of this product can promote fetal lung maturation, which is helpful to improve the survival rate of preterm babies and reduce neonatal respiratory distress syndrome. 2, thyroid powder for pregnancy risk category A. Generally processed from the dried powder of the thyroid gland of domestic animals, containing thyroxine and a small amount of triiodothyronine, which is slowly absorbed orally and has an unstable biological response. 60mg of thyroid powder is equal to about 100ug of levothyroxine, which can be used to treat hypothyroidism combined with pregnancy. The product rarely passes through the placenta, and it is generally believed that it has no teratogenic effect on the fetus. Some data show that the malformation rate of the newborns in 44 cases of pregnant women who used this product in the first three months of pregnancy did not increase significantly.