Does the uterus help support the pelvic structures and its removal cause prolapse?
The uterus and top of the vagina are supported in the pelvis by several attachments to the strong tendons and ligaments of the pelvis bone. I do not know if the scientific names of these areas are important to you — pubovesicocervical fascia, rectovaginal fascia, uterosacral ligaments and cardinal ligaments — but the concept is important to grasp (5). All of these attachments are cut during hysterectomy and as long as they are reattached to the end of the vagina, prolapse should not occur very frequently. You would think that this is a very easy task surgically but those support ligaments are not visable most of the time. They are below a layer(s) of tissue and there may be breaks in those connections at invisible places other than their attachments to the uterus and vagina. For example a common instance of prolapse occurs after hysterectomy for uterine fibroids. The uterus is enlarged and the size alone may support the uterus in the pelvis so that breaks in the ligaments are not app