Staying up late can potentially lead to delayed menstruation. The menstrual cycle usually lasts 28-30 days, with an average of 28 days, and 7 days early or late is within the normal range. However, if menstruation has not occurred beyond 7 days, it is considered delayed. In the event of delayed menstruation, if a woman has recently had sex, she can first rule out pregnancy by using an early pregnancy test or blood HCG test. Menstruation can be affected by many factors, such as mood, location, season, weather, and staying up late, which may delay menstruation. Occasional late nights usually do not affect menstrual changes, but prolonged late nights will upset the balance of the body’s internal environment and affect the brain’s secretion of hormones, thus causing endocrine imbalance and affecting ovarian function, resulting in delayed menstruation, which may lead to serious menopause. Delayed menstruation should be thoroughly examined to find the cause. If there is no organic lesion and the whole endocrine axis is not problematic, it may be a problem of life habits, such as staying up late for a long time, or greater emotional fluctuations. Therefore, women should try to maintain good living habits and happy mood, avoid staying up late, eat a balanced diet and exercise moderately.