Hello! My period is early and the amount is small. What is the reason?

Under normal circumstances, women's menstrual cycle is 28-30 days, menstrual blood volume is 30-50 ml. If the menstrual period is early, and the menstrual blood volume is small, it is likely to be caused by factors such as insufficient qi and blood, endocrine disorders, and may also be the cause of gynecological diseases such as uterine fibroids and endometriosis.