If you have not had your period for more than 10 days or more, it is abnormal. If you are a woman of childbearing age, a blood HCG test should be performed to rule out the absence of menstruation due to pregnancy. If the test is not due to pregnancy, an ultrasound should be performed to understand the thickness of the uterine appendages and the endometrium. If the endometrium is thickened, progesterone can be used orally. Generally, after taking progesterone, most of the menstrual periods will come in 3-7 days after stopping the medication, and a hormone test can be performed to find out if the lack of menstruation is caused by ovarian function. If you are a young girl or an older woman, you may have irregular menstruation due to hormonal disorders. It is recommended to have an ultrasound examination to understand the condition of the uterine adnexa and the condition of the endometrium, and to have a hormone level examination to understand the hormone level, and to give effective cycle adjustment treatment according to the examination results.