A low value of 0.04 uIU/ml of thyroid stimulating hormone in pregnant women may be suffering from hyperthyroidism, which may be more serious, or it may be physiologically low, a condition that is generally not serious. The normal range of thyroid stimulating hormone in pregnant women is divided into three periods. Early pregnancy is between 0.1 and 2.5 uIU/ml, the normal range in mid-pregnancy should be between 0.2 and 3.0 uIU/ml, and late pregnancy should be between 0.3 and 3.0 uIU/ml. Due to the influence of human chorionic gonadotropin in the body after pregnancy, the levels of free thyroxine and thyroid stimulating hormone may fluctuate physiologically, and may be higher or lower than those in non-pregnancy period, which is generally a physiological phenomenon, and usually does not require special treatment, and follow-up observation is sufficient. When a pregnant woman suffers from hyperthyroidism, her thyroid stimulating hormone will be low, and she may have symptoms such as fear of heat and excessive sweating, palpitations, diarrhea, etc., which may cause miscarriage in severe cases. When a pregnant woman finds that her thyroid stimulating hormone is low, it is recommended that she go to the hospital in time to get a clear diagnosis before treatment.