There are many reasons for early menstruation, such as drug factors, diet or mental stress, organic diseases, neuroendocrine dysfunction and so on. 1. Drug factors: long-term use of certain drugs may cause early menstruation, such as anti-tumor drugs, can lead to female endocrine disorders. 2. Excessive diet or mental stress: overeating or excessive dieting may lead to early menstruation; prolonged overwork, mental stress, emotional excitement, etc., can also lead to menstrual disorders, which may lead to early menstruation. 3. Organic diseases: local inflammation of reproductive organs can also cause early menstruation, such as endometritis, tumor, developmental abnormality and so on. 4. Neuroendocrine dysfunction: If the hypothalamus-pituitary-ovarian axis functions abnormally, it will lead to neuroendocrine dysfunction, resulting in early menstruation. There may be other reasons for early menstruation. If the phenomenon occurs for a long time, it is recommended to go to the hospital in time to improve the examination and give standardized treatment after a clear diagnosis.