TSH is the abbreviation of thyroid stimulating hormone. Whether low thyroid stimulating hormone has an effect on pregnancy needs to be determined based on the degree of low thyroid stimulating hormone level and symptoms, and cannot be generalized. The normal value of thyroid stimulating hormone is 2-10mU/L. If thyroid stimulating hormone is slightly low, it usually has no effect on pregnancy, as it does not lead to abnormal sperm vitality in men and endocrine dysfunction in women, and temporarily does not cause abnormal menstrual cycle or amenorrhea, so it will not affect pregnancy. However, if thyroid stimulating hormone is severely low and hyperthyroidism occurs, it may lead to abnormal sperm vitality in men and low or prolonged menstrual flow or even amenorrhea in women, thus leading to menstrual disorders and abnormal ovulation, which will have an impact on pregnancy. If you have hyperthyroidism, you need to apply propylthiouracil tablets, methimazole tablets and other medications under the guidance of your doctor, which can play a role in regulating the function of the thyroid gland and help to restore the stability of your own thyroid hormone levels and reduce the impact on pregnancy.