The following are the causes of early menstruation, low volume and black color: 1. If the menstruation is early for more than 10 days or more, it is caused by endocrine disorder. 2. Low menstrual volume and black color may also be caused by low hormone level, i.e. endocrine disorder. 3. There are many other causes of low menstrual volume and black color, such as insufficient luteal function, low thyroid function or high prolactin, etc., which can cause low menstrual volume. 4. 4. Low menstrual volume and black color can be caused by cold or emotional instability during menstruation. 5. Women often perform uterine operations, such as abortion, hysteroscopy or scraping, which can cause damage to the basal layer of the uterus and cause adhesions in the uterine cavity, which can also cause low menstrual volume and black color. Therefore, some tests should be performed in this case, such as blood test for hormone 6 and thyroid hormone on 2-4 days of menstruation to understand the function of ovaries and thyroid gland. After menstruation, a hysteroscopy can be performed to find out if there are any uterine adhesions and to treat the symptoms and regulate the menstrual cycle according to the test results.