The normal values of T3 are 2.0-6.26pmol/L and free T4 are 10.3-31.0pmol/L (there may be slight differences in different testing methods). It is recommended to control between 0.1-2.5mU/L in early pregnancy, 0.2-3.0mU/L in mid-pregnancy and 0.3-3.0mU/L in late pregnancy. Pregnancy begins with an initial screening of the nail function. If the nail function is normal but combined with a positive thyroid peroxidase antibody and TSH above 2.5mU/L, it is recommended that medication is needed. If the thyroid function is normal, TSH is below 2.5mU/L and thyroid peroxidase antibodies are negative, you can observe temporarily and review thyroid function regularly.