If menstruation is early or late, it is mostly due to endocrine disorders. Therefore, it is recommended to take a blood test for sex hormone 6 on the second day of menstruation to understand ovarian function, estradiol, and other hormone levels to see if there is any abnormality that may cause menstruation to be advanced or pushed back. It is recommended to sit still for 10 minutes before the blood is drawn to ensure adequate rest so that prolactin is not increased due to strenuous exercise. It is also recommended to have an ultrasound examination, mainly to understand the condition of the uterine lining, the thickness of the lining of the uterus, whether there is any abnormal echo in the lining of the uterus, whether there is uneven echo, and then give the necessary treatment.