When a woman has her period in the middle of the night, if it is before 12 o’clock, it will be counted as the same day, and if it is after 12 o’clock, it will be counted as the second day of menstruation. The menstrual period of a woman is within 3-7 days, as long as the woman has normal menstrual discharge and there is no abnormality during this period, it is considered normal. The level of hormones secreted by the ovaries, in the first half of the period, is due to the increased secretion of estrogen to promote the growth of the uterine lining, and in the second half of the period, estrogen and progesterone work together to make the uterine lining grow and thicken, and when these two kinds of hormones are withdrawn, the woman will have her menstruation, and the menstrual period may occur during the day, or at night, so as long as a woman’s menstruation occurs within the normal range, and her menstrual flow is within 30-70 ml, it is considered normal. Therefore, as long as a woman has her period within the normal range, with a normal volume of 30-70ml, it is considered normal.