Pelvic organ prolapse (POP) is descent of the pelvic organs through weakened vaginal support. It is graded by compartment and quantified with POP-Q, and it interacts closely with urinary incontinence — including "occult" SUI unmasked by prolapse reduction.
Classification
- Anterior compartment: anterior vaginal-wall weakness, usually with bladder descent (cystocele).
- Posterior compartment: posterior weakness with rectal bulge (rectocele) ± small bowel (enterocele).
- Apical: descent of uterus/cervix (or vaginal cuff post-hysterectomy), vault, and/or bowel (enterocele).
- An enterocele is a true hernia of intestine into the vaginal wall. Prolapse is most frequent anterior > posterior > apex. Complete uterine prolapse (procidentia) can cause bilateral ureteral obstruction, relieved by correcting the prolapse.
Normal Pelvic Support (3 levels)
- Level I — suspends the uterus/upper vagina to the sacrum and lateral sidewall; loss → apical prolapse.
- Level II — paravaginal attachments of the mid-vagina to the levator fascia and arcus tendineus; loss → anterior wall prolapse/cystocele.
- Level III — lower-third attachments to the perineal membrane, levators, and perineal body; anterior loss → urethral mobility, posterior loss → distal rectocele/perineal descent.
Pathogenesis
- Well-established risk factors (3): age, obesity, and parity (risk rises with childbirths, slowing after the first two).
- Less established (7): smoking, chronic constipation, menopause/hormonal effects, hysterectomy/other pelvic surgery (a strong predictor of repeat pelvic-floor surgery), larger vaginally-delivered fetal weight, genetic predisposition, and race/ethnicity (more common in Caucasian and Hispanic than African-American women).
Incontinence and POP
POP can exacerbate storage LUTS, and >40% of women with SUI have a significant cystocele. UI procedures without POP correction can worsen certain prolapse; POP surgery improves storage symptoms in a significant proportion. Occult SUI is stress incontinence that appears only after prolapse reduction (previously masked) — failure to address it at POP surgery leads to more symptomatic postop SUI. Untreated POP is usually a quality-of-life condition but can rarely cause retention or renal failure from compression.
Diagnosis and Evaluation
- History — the only symptom strongly associated with prolapse at/below the hymen is a sensation of vaginal bulge; coexisting UI, fecal incontinence, and voiding/defecation/sexual symptoms correlate weakly. Evaluate defecatory disorders before POP surgery and discuss dyspareunia (some repairs cause it).
- Physical exam — external genitalia and estrogen status (signs of deficiency: urethral caruncle, urethral prolapse, labial adhesions); assess prolapse ideally in both lithotomy and standing; check anal sphincter tone (S2–4). Imaging plays a small role.
POP-Q System
Six points and three landmarks measured in cm relative to the hymen (negative = above, positive = below):
| Point | Location |
|---|---|
| Aa | Anterior wall 3 cm proximal to the meatus (−3 to +3) |
| Ba | Most distal anterior-wall prolapse (−3 to +tvl) |
| Ap | Posterior wall 3 cm proximal to the meatus (−3 to +3) |
| Bp | Most distal posterior-wall prolapse (−3 to +tvl) |
| C | Cervix (or vaginal cuff) |
| D | Posterior fornix (distinguishes cervical elongation from uterine prolapse) |
Landmarks: gh (genital hiatus), pb (perineal body), tvl (total vaginal length).
Staging (most severe point on straining): Stage 0 — no prolapse (Aa/Ba/Ap/Bp all −3); Stage 1 — >1 cm above the hymen; Stage 2 — within 1 cm of the hymen; Stage 3 — >1 cm below the hymen but not fully everted; Stage 4 — complete eversion (≥2 cm < tvl). Asymptomatic stage 1–2 is considered normal.
Management
- Anterior: pessary or prolapse repair.
- Apical: sacrocolpopexy (rare sacral pain/osteomyelitis). CARE trial — in women with prolapse but no preoperative SUI undergoing sacrocolpopexy, adding a Burch significantly reduced postoperative incontinence at every follow-up point.
- Posterior: rectocele repair (mesh-augmented repairs risk levator/gluteal pain and rectal penetration).
- The 2011 FDA safety communication concerned mesh placed transvaginally for POP and specifically excluded slings and transabdominal prolapse mesh.
Self-Test
1. Which organs are involved in anterior, apical, and posterior prolapse — which is most/least common, and which support level is lost? Anterior — bladder (cystocele), level II, most common; apical — uterus/cervix/vault ± bowel, level I; posterior — rectum (rectocele) ± bowel (enterocele), level III, least common.
2. List risk factors for POP. Age, obesity, parity (well-established); smoking, chronic constipation, menopause, prior hysterectomy/pelvic surgery, larger fetal weight, genetics, Caucasian/Hispanic ethnicity.
3. What do the Aa, Ba, Ap, Bp, C, and D points signify? Aa/Ap — anterior/posterior wall 3 cm proximal to the meatus; Ba/Bp — most distal anterior/posterior prolapse; C — cervix or cuff; D — posterior fornix.
4. Describe the POP-Q stages. 0 — no prolapse; 1 — >1 cm above hymen; 2 — within 1 cm of hymen; 3 — >1 cm below but not fully everted; 4 — complete eversion.