Menstruation that is pink in color is abnormal. This is because normal menstrual blood is dark red and contains not only blood, but also shed endometrium as well as cervical mucus and epithelial cells of the vagina. If the menstrual period is pinkish in color, it means that the blood is diluted, commonly due to inflammation of the endometrium or inflammation of the uterine body itself, which increases exudation, diluting the blood and making it lighter in color. In this case, it is best to have an ultrasound examination after menstruation clears, mainly to understand the thickness of the endometrium and whether the endometrial echo is uniform, and then decide whether treatment is needed based on the results. If the endometrium is thickened and the echogenicity is uneven, it is considered to be caused by inflammation of the endometrium. It is recommended that a diagnostic curettage needs to be done at the 6th-12th hour of menstruation. It is also important to rule out blood thinning caused by anemia, which turns the menstrual flow pink.