Thyroid disorders are one of the common diseases among Chinese women of childbearing age and women in the first half of pregnancy. Thyroid disorders during pregnancy include clinical hypothyroidism, subclinical hypothyroidism, positive thyroid autoantibodies, and hyperthyroidism during pregnancy. The prevalence of these disorders among women in the first half of pregnancy is 0.6%, 5.27%, 8.6%, and 0.4%, respectively, which means that 1 out of 10 mothers-to-be may be affected by such disorders. Hypothyroidism in pregnancy is one of the factors that cause neurointellectual impairment in the offspring. The first 12 weeks of gestation are the first period of rapid fetal brain development, but at this time the fetus’ own thyroid function is not yet established, and the fetal brain is completely dependent on the mother for the supply of thyroid hormones needed for development. If the mother-to-be suffers from hypothyroidism during this period, it will directly affect the fetal brain development and even cause irreversible damage. Positive thyroid autoantibodies can greatly increase the incidence of miscarriage and premature birth. Pregnant women with moderate or severe hyperthyroidism during pregnancy and those with uncontrolled symptoms have significantly higher rates of miscarriage, preterm delivery, hyperemesis and perinatal mortality. It is evident that thyroid function screening before pregnancy and early in pregnancy is crucial. In order to promote the screening of thyroid disorders during pregnancy, China has officially issued the “Guidelines for the diagnosis and treatment of thyroid disorders in pregnancy and postpartum (2012)”, recommending that hospitals and maternal and child health departments in China should carry out screening with serum TSH, FT4 and TPOAb as the screening indicators, and the timing of screening should be chosen before 8 weeks of gestation, preferably before pregnancy, so that thyroid indicators can be screened. Once the disease is diagnosed, effective treatment before pregnancy can be chosen to ensure the maximum health of mother and child. In addition, the Guidelines recommend that levothyroxine (L-T4), which is economical, effective and safe, should be the first choice for patients with clinical hypothyroidism during pregnancy. Pregnant women with clinical hypothyroidism and subclinical hypothyroidism should have their thyroid function tested every 4 weeks from 1 week to 20 weeks of gestation, and at least once from 26 weeks to 32 weeks of gestation. Pregnant women with thyroid autoantibodies who have normal thyroid function should have their serum TSH tested every 4 to 6 weeks from 1 week to 20 weeks of gestation and at least once more from 26 to 32 weeks. In women with existing hyperthyroidism, it is best to consider pregnancy after thyroid function has been controlled to normal.