The endometrium of female patients will show cyclical changes. When the thickness of the endometrium reaches 7mm, it means that menstruation will occur soon. During menstruation, the endometrium will be shed from the uterine cavity and flow out of the body with the menstrual blood, and after the end of menstruation, there will be a manifestation of the endometrial hyperplasia phase. As the endometrium thickens into the secretory phase, when the endometrium reaches about 7-10mm and enters the menstrual phase, the small uterine arteries gradually appear to twist and subsequently rupture and bleed, which causes the formation of menstrual blood and a new menstrual cycle, which is a normal physiological phenomenon for women and does not require treatment. Under the influence of certain disease factors, the endometrium appears to have 7mm during the hyperplasia phase, which can cause irregular vaginal bleeding and requires timely diagnosis and treatment of the disease.