When a woman has a heavy menstrual flow with blood clots, it may be due to the following reasons: 1. Multiple fibroids in the uterus, because when a woman has multiple fibroids in the uterus, the size of the uterine cavity increases and the fibroids affect the contraction of the uterus, resulting in heavy bleeding during menstruation. This is due to the fact that women with adenomyosis have a larger uterine cavity, which also causes progressive menstrual pain. 3. This is because the endometrial lining is thickened and cannot be repaired in time, resulting in heavy bleeding, which can easily cause anemia in women. 4. It may also be a normal physiological manifestation, in which the menstrual volume is usually around 60-80 ml, and the menstrual blood may be accompanied by blood clots after discharge.