The period is always early in clinical terms means that the menstrual cycle is often shortened, and the most important reasons are the following: 1. The most common reason is caused by endocrine disorders. If the corpus luteum shrinks early due to some reasons, the menstrual cycle will be shortened and the period will be early; 2. Caused by some diseases, such as submucosal fibroids, which cause a relative increase in the endometrial area, it will cause a relative shortening of the menstrual cycle; 3. Caused by polyps in the endometrium, if there are relatively large polyps in the endometrium, it will also cause symptoms of early menstruation in clinical practice; 4. If it is coagulation dysfunction or thrombocytopenia and other internal diseases can also cause early menstruation. Therefore, it is recommended to do detailed examination, such as blood routine, coagulation time, sex hormone six, ultrasound examination and so on.