The menstrual bleeding clots can be seen in the following aspects: 1. Most of them are physiological phenomena, the endometrium will be exfoliated during the formation of menstruation, the exfoliated endometrium and the menstrual blood will interact with each other and coagulate into clots, which will appear in the menstrual blood with blood clots. 2. Excessive hyperplasia of the endometrium, if the ovarian secretion of estrogen and progesterone function disorders, the elevated level of estrogen makes the endometrium hyperplasia, a large number of endometrium 3, cold invasion, whether it is eating too cold food or the ambient temperature is too low, so that the cold invades the body and the uterus, will affect the discharge of menstrual blood and the formation of clots. 4, gynecological inflammation, endometritis is the most common gynecological inflammatory disease that causes menstrual blood to clot, mainly due to the local inflammatory secretions and menstrual clots. This is mainly due to the interaction of local inflammatory secretions with menstrual blood, which changes the nature of menstrual blood and leads to the formation of blood clots.