Auntie generally refers to menstruation. Suddenly, the menstrual flow is small and dark, which is generally considered to be caused by endometrial adhesion, endocrine disorders or gynecological inflammation. 1. Endometrial adhesion: When you have had a purging or medication abortion, it is easy to damage the endometrial lining of the uterus, causing adhesions in the uterine cavity, thus causing abnormal menstruation, which may also be manifested as a small amount and dark color. 2. Endocrine disorders: when endocrine disorders, abnormal ovarian function, and reduced levels of estradiol, menstruation will appear in small amount and dark color. 3. Gynecological inflammation: When there is gynecological inflammation, such as endometritis, pelvic inflammatory disease, etc., it will cause the phenomenon of low menstrual flow and dark color. When menstruation is suddenly light and dark in color, it is recommended to go to the hospital in time for examination in order to clarify the cause of the disease and treat the symptoms.