The normal menstrual cycle, which is 21-35 days, is 7 days early or 7 days postponed is the normal range and is not treated. Occasionally, another period that is more than 7 days early is not a big problem, but a period that is 10 days early for 3 consecutive months is a shortened menstrual cycle. The most common reason for a shortened menstrual cycle is follicular dysplasia, which means that the follicular phase is shortened and hormone secretion is not normal. Therefore, if your period is more than 3 months early, you need to go to the hospital for endocrine examination and ultrasound. In some cases, pelvic tumors and uterine tumors may cause abnormal menstruation, so early menstruation needs to be checked and treated accordingly.