Pelvic organ prolapse occurs when the pelvic floor weakens and the organs in the pelvis, like the uterus and bladder, drop down into or protrude out of the vagina. The document discusses the anatomy of the pelvis and pelvic floor, factors that can contribute to prolapse, how prolapse is evaluated and classified, and treatment options like surgery and pessaries. Conservative treatments focus on protecting and strengthening the pelvic floor through lifestyle changes.