Subclinical hyperthyroidism may affect menstruation. Subclinical hyperthyroidism means that in the thyroid function test, such as thyroid function triple test or thyroid function penta test, it is found that the thyrotropin hormone is on the low side, while the T3, T4, FT3, FT4 indexes are normal, which may affect the menstruation and lead to abnormal menstruation, such as excessive menstruation, low menstruation and so on, and may even lead to early amenorrhea of a woman. If subclinical hyperthyroidism is detected, it is recommended to cooperate with professional endocrinologists to carry out standardized treatment in time, including medication, iodine 131 treatment, etc., in order to control the condition in time. Otherwise, subclinical hyperthyroidism without timely treatment and control will not only affect menstruation, but may also lead to the development of clinical hyperthyroidism, and even jeopardize the patient’s heart health.