The normal value of TSH (Thyroid Stimulating Hormone) is 0.27~4.2uIU/mL. Whether it is serious or not when TSH is <0.001uIU/mL depends on the cause of the abnormality, which may be related to pituitary gland disease, pregnancy, hyperthyroidism, etc. It is more serious, and can be improved by general treatment, medication or surgery. 1. Pituitary disease: Women who suffer from hemorrhage during pregnancy or childbirth may have hypopituitarism and low thyroid stimulating hormone. This kind of low thyroid stimulating hormone occurs, thyroid hormone will also be low, and all the laboratory tests are low, indicating hypopituitarism, which can be treated by oral hydrocortisone and levothyroxine sodium. 2. Pregnancy: after pregnancy, women may have transient low thyroid hormone, in life, pay attention to rest, keep the mood relaxed and happy, appropriate dietary supplements, etc., and pay attention to the monitoring of the condition, follow up the follow-up examination, etc., under the guidance of the doctor diagnosis and treatment, and can be applied to the antithyroid medication if necessary. 3. Hyperthyroidism: patients should take proper rest, avoid emotional excitement, infection, overwork, avoid iodine diet, can follow the doctor's instructions to take antithyroid drugs, such as methylthiouracil, etc.; β-blockers, such as metoprolol, etc., for treatment, for the serious condition of the patient can be treated by radioactive iodine therapy or surgical treatment, in order to improve the symptoms. If you have low TSH, we recommend you to go to the hospital, actively cooperate with the doctor's treatment, and pay attention to monitoring your condition and regular checkups in your life.