What causes a prolapsed rectum?

Loose pelvic muscles. A prolapsed rectum occurs because the supporting muscles and ligaments have loosened due to age, illness of connective tissues, pregnancy, obesity, or other conditions that cause pelvic floor weakness. This needs surgical repair to prevent complications.
Weak tissues. The supportive tissues around the rectum holding it in place have become weakened, therefore the rectum begins to protrude and telescope out of the anus.