Delayed menstruation is usually caused by pregnancy if a woman is of childbearing age. If the pregnancy situation is excluded, the common causes of delayed menstruation mainly include mental psychological factors, drug factors, endocrine abnormalities, organic lesions, excessive weight loss, etc.: 1. Mental psychological factors: This is the most common cause of delayed menstruation in women, such as academic pressure, work pressure, emotional stress, depression, etc., may lead to delayed menstruation. But this kind of delayed menstruation is usually transient. With the improvement of mood and emotion, menstruation will come; 2. Drug factors: If patients have taken drugs containing progestin or long-acting contraceptives, menstruation may be delayed when they suddenly stop taking them; 3. Endocrine abnormalities: The most common ones are polycystic ovary syndrome, hyperprolactinemia, abnormal thyroid function and other specific endocrine diseases, which often have delayed menstruation The clinical manifestations of these atopic endocrine diseases often have delayed menstruation and have their own specific hormone expression characteristics, which need to be identified and treated; 4. Organic lesions: for example, when patients have thickened endometrium, menstruation will be delayed for a longer period of time, and patients are usually advised to do ultrasound to measure the thickness of endometrium. If the endometrium is thick, it is recommended that progestin-like medications be given to promote the onset of menstruation. If there is a history of uterine operation, the delayed menstruation may be due to damage to the basal layer of the endometrium or uterine adhesions; 5. Excessive weight loss: Some women lose excessive weight due to the pursuit of a perfect figure, leading to nutritional imbalance and endocrine disruption, resulting in delayed menstruation accompanied by decreased immunity. If the delayed menstruation is due to this cause, patients are advised to stop losing weight immediately, maintain good work and rest as well as living habits, and lose weight in a healthy and moderate way.