1. Damage to the supporting tissues of the pelvic floor from the increase in uterine weight and change in mechanical direction during pregnancy, as well as damage during vaginal delivery. The weight of the uterus gradually increases with the progress of pregnancy, and the position of the uterus in the pelvic and abdominal cavities gradually becomes vertical, thus causing an increasing force to press directly on the supporting tissues of the pelvic floor. Vaginal delivery, especially difficult delivery or prolonged second stage of labor, is an important risk factor for the occurrence of pelvic organ prolapse, which may be related to direct damage to the fascial support structures and vaginal wall in the pelvis, as well as direct or indirect damage to the pelvic floor muscles and nerves. 2. The decline of estrogen leads to the relaxation of pelvic floor tissues. Estrogen is one of the important substances necessary to maintain the tissue structure, tension, collagen content, blood supply and nerve regeneration of the pelvic floor. 3. Postpartum obesity is an independent risk factor for the occurrence of POP. Most studies on POP have shown that overweight and obese women have a higher risk of developing the disease, and the results of a cross-sectional study of 27,342 women by Hendrix et al. suggest that obesity is a risk factor for uterine prolapse and anterior and posterior vaginal wall bulge. A multifactorial logistic regression analysis showed that the risk of pelvic organ prolapse was 1.885 times higher in those with body mass index ≥24 kg/m2 than in those with <24 kg/m2.