A period of 1 week is normal, as a normal period usually clears in 3-7 days. If it is less than 3 days clinically it is abnormal; if it is more than 9 days, it is abnormal uterine bleeding. Normal menstrual flow is 35ml-58ml at a time. Menstrual blood is dark red in color and contains, in addition to blood, endometrial debris as well as cervical mucus and vaginal exfoliated cells, and menstrual blood is non-coagulable. If small clots are found in menstrual blood, this is normal. It is also normal for most people to experience lower abdominal back pain during menstruation. During menstruation, do not do heavy physical work, do not have sex, and do not do strenuous exercise.