Endogenous factors Inheritance, race, development, body type, etc.; Exogenous factors (acquired) Nutrition, obesity, natural deterioration of muscle function, other internal diseases (constipation, chronic chronic bronchitis), Liu Yuling, Department of Obstetrics and Gynecology of the Second Affiliated Hospital of Zhengzhou University, increase in abdominal pressure, bad habits (constipation), occupation (strenuous physical activity), senility, menopause; Injury Obstetrical factors: the course of a woman’s pregnancy and childbirth (e.g., birth injury, assisted labor, macrosomic fetus, excess amniotic fluid, prolongation of labor, etc.) Gynecologic factors: pelvic surgery, oestrogen deficiency.