There may be more reasons for having a small amount of menstruation, but first rule out the possibility of conception. Pregnancy may be present when no contraceptive measures are taken at the time of conception. Pregnancy may cause a small amount of bleeding when it is in bed, and even a small amount of bleeding may occur when progesterone and human chorionic gonadotropin are low and a pre-term abortion occurs, which may be treated accordingly. When there are changes in endocrine hormones or staying up late, it may cause menstruation to come only a little and then end. When there is inflammation of the cervix or vaginal congestion, it may also cause a small amount of bleeding, which usually does not end so early. It is advisable to observe the amount tomorrow. If the amount increases tomorrow, it means that it is menstruation.