If a woman has more menstrual flow during the day and less at night, it is a normal clinical manifestation, mainly due to work and rest habits. Women need to walk, run or stand for a longer time during the day due to many reasons such as work, life and traffic. These activities will promote the contraction of the uterus, which will cause the accumulated blood in the uterine cavity to be discharged out of the body quickly under the effect of gravity and uterine contraction. So during the day women have more vaginal bleeding and can use 3-4 or 4-5 tampons per day when they have heavy periods. At night, women spend most of their time sleeping and lying down is not conducive to uterine contraction, while the position of the uterus changes to a flat position with the uterine fundus at its lowest point. This causes the blood to collect at the base of the uterus instead of being discharged through the cervix, and only a small amount of blood is discharged when there is more blood, so the amount of vaginal bleeding is relatively low at night.