During pregnancy, due to the gradual enlargement of the uterus, the muscles and soft tissues of the pelvic floor are damaged to varying degrees, which destroys the chronic traction of the pelvic floor on the uterus and other organs. The change of hormone level during pregnancy leads to the change of collagen metabolism in pelvic floor connective tissue, which further weakens the supporting function of pelvic floor. During childbirth, pelvic floor muscles lose innervation and elasticity. After muscle stretching, the supporting force is insufficient, resulting in corresponding dysfunction.