Delayed menstruation in patients without pregnancy may be related to mental factors, tumor factors, gynecological diseases and so on. 1. Psychological factors: when the patient has long-term mental tension, stress, or environmental changes, depression, etc. may affect the neuroendocrine abnormality, leading to menstrual abnormality, thus causing menstrual delay. 2. Tumor factors: when the patient has ovarian tumor with secretion function, pituitary microadenoma, etc., it may also cause menstrual abnormality and delayed menstruation or no menstruation. 3. Gynecological diseases: Some common gynecological diseases, such as polycystic ovary syndrome, premature ovarian failure, etc., may also lead to prolonged menstrual cycle, decreased menstrual flow or delayed menstruation. When menstruation is delayed, it is recommended that the patient should consult a doctor in time for examination and targeted treatment after clarifying the condition, maintain a good mood in life, pay attention to rest, avoid staying up all night or overworking, and at the same time, pay attention to the observation of the condition and regular follow-up.