The duration of menstruation is usually 3 to 5 days, and a small amount of brown fluid before and after each period is normal. The amount of bleeding is between 30 and 80 ml, with the most on the second to third day. This number of milliliters may not be understood, so let’s take the sanitary napkin used during the day to measure. When half of the sanitary napkin is wet with blood, we count it as a sanitary napkin. Usually 6-8 sanitary napkins will be enough for a menstrual period. If 15 sanitary napkins are wet, it is too much. Less than 2-3 sanitary napkins is a low menstrual flow. Menstrual blood is usually dark red in color, does not clot, and contains endometrial debris, cervical mucus and vaginal epithelial cells in addition to blood. Generally women have no symptoms during menstruation, a few may have discomfort such as lower abdomen or lumbosacral cramping, breast pain, constipation or diarrhea, headache, etc. It usually does not affect daily work, study and life. The last menstrual period is the most recent one from the date of consultation, and the menstrual cycle should be calculated from the first day of bleeding. However, it is important to note that the last menstrual period means that it is of the same duration, about the same volume and about the same date as usual. Do not mistake abnormal vaginal bleeding for menstruation. This type of bleeding is usually less or more than menstruation, shorter or longer, or loses the usual pattern of menstrual flow. It is also normal for some people who are about to have their period or have intercourse right after it ends and end up with a small amount of blood after intercourse. This is because the endometrium has not been repaired and the uterus has been stimulated.