Free thyroxine is low, to analyze the specific problem: 1, if slightly low, free thyroxine is low that is, thyroid stimulating hormone TSH will be high, it is generally believed that if TSH>10mU / L or if TSH did not exceed 10mU / L, but the blood lipids, especially cholesterol is higher, you can continue to observe, you should be regularly reviewed, to observe hormone changes, three months later Or review once every six months to see if there are any major changes or not. If free thyroxine is low during pregnancy, it is actually more harmful and should be treated actively, otherwise it will affect the development of the fetus; 2. If the thyroid is low, reflecting the indicator that TSH is higher than 10mU/L or the patient’s cholesterol is high, the patient should be given supplemental thyroxine treatment to control it within a more desirable range.