Prolapse is deﬁned as any descent of the uterus down the vaginal canal, so that it lies below the normal position in the pelvis. In the extreme, this may result in the uterus descending beyond the vulva to a position outside the body (procidentia). Some degree of uterine descent is common in parous women.
The etiology and mechanism of a descensus of the uterus are fundamentally the same as those associated with retrodisplacement or the formation of a cystocele, enterocele, or rectocele: Loss of normal structural support as a result of trauma (childbirth), surgery, chronic intraabdominal pressure elevation (such as obesity, chronic cough, or heavy lifting), or intrinsic weakness. The most common sites of injury are the cardinal and uterosacral ligaments and the levatorani muscles that form the pelvic ﬂoor, which may relax or rupture. Rarely, increased intraabdominal pressure from a pelvic mass or ascites may weaken pelvic support and result in prolapse. Injury to or neuropathy of the S1 to S4 nerve roots may also result in decreased muscle tone and pelvic relaxation.
Retroversion of at least second degree is almost always concurrently present, as explained by plainly mechanical reasons: intraabdominal pressure forces the uterus directly downward, stretching all three sets of pelvic supporting structures, when the uterus, with the patient upright, is in a vertical or backward position.
Descent that does not involve protrusion of the cervix at the introitus is known as ﬁrst-degree or second-degree prolapse based upon the distance toward the introitus. When only the cervix reaches the introitus or slightly protrudes, third-degree prolapse is present. If the entire uterus is pushed outside the introitus, a complete procidentia (fourth-degree prolapse in some numbering schemes) exists.
Because of the intimate association of the bladder with the cervix, prolapse of the uterus generally draws down the bladder and produces an accompanying cystocele. The laxity of structures constituting the pelvic ﬂoor, not being restricted to the uterovesical relations, leads to complete asthenia of the pelvic outlet, so that rectocele also is a frequent complication of prolapse. Enterocele is always present in procidentia, where the cul-de-sac of Douglas is brought down with the uterus and frequently contains loops of intestine or omental tabs. Because of chaﬁng and irritation of the exteriorized cervix, ulcerations and erosions frequently occur. Surprisingly, cervix carcinoma is an uncommon ﬁnding in such irritated areas.
Prolapse may be associated with multiple complaints, ranging from functional bleeding and backache to the more common “heavy” or “bearing-down” feeling in the pelvis, urinary difﬁculties, and constipation. There may also be new-onset or paradoxical resolution of urinary incontinence. Each of these symptoms must be evaluated in the light of experience and judgment before attempting surgical correction. The patient’s age, desire for fertility, and personal preferences should all enter into the equation in deciding upon correct management. It should be kept in mind that retroversion by itself is almost never a decisive factor in clinical complaints, that most backaches are due to reasons other than retrodisplacement, and that incontinence and urinary frequency may disappear following treatment of underlying urinary tract diseases. Surgical or pessary therapy may even make some symptoms (such as urinary incontinence) worse.
With these factors well in mind, the surgeon has a wide variety of procedures at his or her disposal to suspend the uterus, bladder, and vesicle neck and repair the pelvic diaphragm. Minimal prolapse does not require therapy. For those with more severe prolapse or symptoms, pessary therapy, surgical repair, or hysterectomy (with colporrhaphy) should be considered. Postmenopausal women should receive estrogen and progesterone replacement therapy for at least 30 days before pessary ﬁtting or surgical repair.