The normal physiological cycle of a woman, i.e. menstruation, is 21-35 days, and it is usually normal to have an early or delayed period of no more than 7 days. Menstruation is the cyclical shedding of the endometrium and the normal physiological cycle is 21-35 days, with an average of 28 days. The number of days in the menstrual cycle is not absolutely fixed, but may fluctuate slightly, and it is normal to have a period that is 7 days early or delayed. If your period is delayed for more than 7 days, women of childbearing age who are sexually active should take an early pregnancy test to determine if they are pregnant. After ruling out pregnancy, it is also necessary to consider whether there is a change in work and rest routine, significant mood swings, mental stress, staying up late or taking medication. In short, occasional delayed menstruation is not a big problem, but if it is regularly delayed for more than 1 week, it is recommended that the patient should go to the hospital for gynecological ultrasound and sex hormone six tests to clarify the cause of delayed menstruation and carry out targeted menstrual regulation treatment.