If the amount of menstruation is very low and dark in color when menstruation comes after abortion, it may be caused by the following reasons: First, it is highly suspected that the endometrial damage has caused partial adhesion in the uterine cavity, which leads to a significant decrease in the amount of menstruation, and the ultrasound examination often reveals that the endometrial lining is relatively thin and the echo is not uniform. Secondly, it may be caused by endocrine disorders, after the abortion, there will be anxiety, there will be worried about the body, which will lead to endocrine disorders, and the phenomenon of low menstrual flow and dark color. Third, it may be caused by inflammation, often accompanied by pain in the lower abdomen, it is recommended to combine with the clinical history of the examination to make a preliminary diagnosis. If there are adhesions in the uterine cavity, it is recommended to do hysteroscopy as soon as possible to separate the adhesive tissues.