Foreign literature reports that the incidence of clinical hypothyroidism in pregnancy is 0.3%~0.5%, and the diagnosis relies on laboratory tests. Even without clinical manifestations, TSH intervenes between 2.5~10.0mIU/L (early pregnancy), or 3.0~10.0mIU/L (mid-late pregnancy) with reduced FT4 levels, or regardless of FT4 levels, as long as TSH>10.0mIU/L. Hypothyroidism in pregnancy can be diagnosed. Pregnant women with hypothyroidism are more likely to suffer from obstetric complications such as miscarriage, anemia, hypertension, placental abruption, and postpartum hemorrhage. Untreated hypothyroidism in pregnancy can lead to increased incidence of preterm birth, low birth weight, neonatal respiratory distress syndrome, and increased risk of embryonic death. In humans, thyroid hormones are essential for fetal brain development, and a 1999 US study showed that the IO scores of the offspring of untreated gestational hypothyroidism were lower than the mean values of the offspring of normal pregnant women. A decrease in FT4 in early gestation can result in a low developmental index at 10 months of age, and if low FT4emia persists beyond 24 weeks of gestation, it can reduce behavioral cognitive scores in offspring by 8 to 10 points. If FT4 levels return to normal on their own in the second trimester, then offspring development will not be affected. Risk factors for maternal hypothyroidism in pregnancy include maternal age over 30 years, comorbid other autoimmune diseases, previous neck radiation therapy, use of medications that affect thyroid function (e.g., amiodarone, lithium carbonate, etc.), use of iodine-containing contrast media, persistent positive TPOAb, family history or past history of thyroid disease, presence of a thyroid mass or symptoms of hypothyroidism. Screening for thyroid function in high-risk pregnant women only misses 56.7% of clinical and subclinical hypothyroidism and 64.7% of clinical and subclinical hyperthyroidism. If not influenced by economic factors, I believe that screening for thyroid disease can be carried out during the preparation period or early pregnancy in areas where it is available, and our hospital will actively cooperate with the obstetrics and gynecology department to expand publicity and increase public awareness of the dangers of hypothyroidism.