There are some pregnant women who are found to have low thyroid function during pregnancy physical examination. If during the first 3 months of pregnancy, FT4 is low and sTSH is high, correct it quickly and make up for it, it can still make up for the previous deficiency. In particular, but not absolutely, as long as FT3 and FT4 reach the normal range, it is appropriate to control s-TSH below 3 in the middle and late pregnancy thereafter, however, a slightly higher s-TSH is not a big problem. If hypothyroidism is detected in the middle or late stages of pregnancy, ultrasound is needed to assess the fetal development. If FT4 is low for a long time, it will definitely affect the fetal development. Correct the hypothyroidism as soon as possible. If hypothyroidism persists after delivery, take thyroxine and breastfeeding has little effect on the pediatric population. You can take thyroxine tablets in the morning on an empty stomach. If a woman has a family history of thyroid disease, or has a history of spontaneous abortion, has autoimmune diseases such as rheumatoid arthritis, vitiligo, etc., do thyroid function tests well before pregnancy. Within 1 year after delivery, thyroid function needs to be tested. Early detection of postpartum thyroiditis, Hashimoto’s thyroiditis or GD.