The said endometrium falls out, that is to say, when menstruation, there are large pieces of endometrium out of the called membrane-like menstruation, the reason why the membrane-like menstruation, often because of the following reasons: 1, due to the excessive activity of the endometrium, so in the menstruation, the endometrium is not in the form of fragments out of the endometrium, but in the form of a large chunk of tissue out of the endometrium, which often causes menstrual cramps. Because the large chunks of endometrium are discharged from the uterine cavity and require uterine contractions to be discharged, pain in the lower abdomen can occur.2. Because the endometrium itself is inflamed, the tissue is relatively brittle, and large pieces of endometrium are also dislodged when the endometrium is dislodged, and this can manifest itself as a large piece of rotting tissue-like material being discharged in the menstrual blood.