Women have more menstruation on the first day and less on the second day probably due to the large amount of menstrual blood caused by the shedding of the endometrium on the first day of menstruation and less bleeding on the second day due to the shedding of the endometrium the day before, when the endometrium has become thinner. Menstrual blood is a mixed fluid made by mixing a woman’s blood with shed endometrium and cervical mucus. It is more normal to have a high flow at the beginning of menstruation, and the flow should show a gradual decrease in the following days. Under normal circumstances, a woman should have a bleeding volume of between 20-60 ml for one menstrual period and a period of between 3-7 days. It is recommended that you can first observe whether the menstrual flow is less than 20ml or the period is less than two days and other menstrual periods. If the menstruation is normal and regular, it is normal for it to occur once in a while.