If the menstrual flow is low and black, first of all, you need to except whether you have had an abortion, clearing the uterus, scraping several times on the menstruation are affected. Commonly, there are two aspects of low menstruation: First, it is a short time change such as work stress or cold, business trip, going abroad, etc., there may be low menstruation, and it will change after normal life. If there are several abortions or recent abortion, scraping or purging, low menstruation indicates a problem. How to distinguish between these two cases: 1. According to the medical history, blood tests, blood values, which is to check the endocrine, A function, in addition, the main observation is ultrasound, endometrial thickness, if the endometrium after ovulation, that is, after 14 days of menstruation to the endometrium before menstruation are very thin, and have done abortion, scraping, it means that the endometrium is damaged, menstruation will be less. If there are no such cases, it may be caused by emotional changes, cold, change of environment such as going abroad, etc., which occurs once in a while. There is no endocrine problem at the time of examination, and the endometrium is normal. In general, after menstruation, the endometrium is 0.6cm, 0.4cm; but the endometrium before menstruation are about 1.0cm; if the endometrium continues to be 0.3cm, 0.4cm, even before coming to menstruation is still 0.5cm, 0.6cm, it means that the endometrium is damaged.2. In addition, if there is little menstruation due to having had abortion, the first thing to do is to exclude the uterine adhesions, uterine Endometrial thinning can be distinguished by doing laboratory tests and hysteroscopy, so according to each person’s situation is different, determine which aspect they belong to, from which aspect to check, to describe the condition in detail to the doctor, to seek medical attention in a timely manner. Second, if this menstruation is low and black, then also check if you are pregnant, and confirm the diagnosis by taking a blood test or checking urine. If you are pregnant, you need to check again whether it is an intrauterine pregnancy or an ectopic pregnancy. So have a detailed conversation with the doctor according to your situation, who will do the appropriate tests according to the patient’s condition.