Whether it is normal for menstruation to come a week early is determined by specific reasons. The normal menstrual cycle is usually 21-35 days, a week early or a week late is a normal physiological phenomenon, menstruation is affected by many factors, such as the environment, emotions, diet, endocrine, etc. If the menstrual cycle is normal, life and diet, no major changes in the environment, occasionally a week early is normal. However, early menstruation may occur under certain pathological conditions. For example, poor luteal function, premature atrophy of the corpus luteum, endometrial polyps, etc., may also cause shortening of the menstrual cycle. Having taken the emergency contraceptive pill orally in the recent past, drug-induced withdrawal bleeding can occur, which can also cause early menstruation. Therefore, if you experience a week early menstruation, you need to actively rule out other problems. If there are no medications or other diseases, it is normal and does not need to be treated. If there are other diseases, active examination and treatment is needed.