Vaginal bleeding occurs whether a woman has a normal period or an unplanned miscarriage. However, there is a difference between a period and a miscarriage. The difference can be made in terms of the nature of the bleeding, the amount of bleeding, the length of the bleeding, and whether there is tissue of the pregnancy sac in the blood. First of all, the essence of menstruation and miscarriage is different. Normal menstruation is a physiological phenomenon, and in the case of regular menstruation, the time of menstruation is around 28-32 days. Miscarriage, on the other hand, is a pathological phenomenon caused by a variety of factors, which occurs after pregnancy due to the poor development of the fertilized egg, trauma to the body, etc. Secondly, in terms of the amount of bleeding, menstrual bleeding is less than that of miscarriage, and they can differ in terms of color. Menstrual periods are usually dark red in color and contain relatively crushed polyp-like tissue, which is the shed endometrium, while miscarriages appear with brighter blood and contain a larger gestational sac. The third and most fundamental difference between a period and a miscarriage is the concentration of HCG in the blood. The normal HCG concentration value for a period is less than 5, but in the case of a miscarriage the HCG concentration value in the blood is higher than the normal reference range. Therefore, if women want to know whether it is a period or a miscarriage, in addition to observing the various conditions of bleeding, it is best to go to the hospital to have a blood HCG test to determine.