Clinical overview
Pelvic organ prolapse (POP) is the descent of one or more of the pelvic organs — bladder, uterus, bowel, or vaginal vault — into or through the vagina, the consequence of failure of the connective-tissue, muscular and fascial supports of the pelvic floor. It is very common: the lifetime risk of surgery for prolapse or incontinence has historically been quoted at around 1 in 9–11 women, and prevalence rises steeply with age and parity. Although benign, prolapse can be deeply distressing — women describe a vaginal bulge or "something coming down", pelvic pressure or dragging that worsens through the day and on standing, and associated bladder, bowel and sexual dysfunction.
Because this objective centres on aetiology, classification and causes, the weight of this chapter is the why and the what — the support anatomy that fails, the compartments that prolapse, the standardised language (POP-Q) used to describe it, and the risk factors that overload or weaken the system — before a working account of assessment and management. Two framing points anchor everything that follows. First, prolapse is a disorder of support, not of the organ itself: the bladder behind a "cystocele" is normal; it is the anterior vaginal wall support that has given way, so the suffix "-cele" names the bulging vaginal wall, not a herniated organ. Second, prolapse, urinary incontinence (Urinary incontinence) and voiding difficulty/retention (Urinary retention) frequently coexist and interact — repairing one can unmask or relieve another. Surgical practice has been substantially reshaped by the national pause on transvaginal mesh, returning native-tissue repair to the centre of care. This chapter links to Urinary incontinence, Urinary retention, and Climacteric and menopause (oestrogen and connective tissue).
Core knowledge
The support system that fails — DeLancey's three levels
Figure C3.1 — How loss of support produces prolapse: DeLancey's three levels predict the compartment (apical/vault, cystocele, rectocele, enterocele as the true hernia), with levator + endopelvic fascia as the active and passive supports.
Pelvic support is provided by the levator ani muscles (the active, tonically contracted floor that keeps the urogenital hiatus closed) and the endopelvic fascia (the passive connective-tissue suspension). When the levator is damaged — classically by avulsion from the pubic ramus during vaginal birth — the hiatus widens and load is transferred to the fascia, which is not designed to bear it indefinitely; the muscular and fascial failures therefore compound one another. DeLancey described three levels of vaginal support, and the level that fails predicts the type of prolapse:
- Level I — apical suspension: the uterosacral and cardinal ligament complex suspends the cervix and upper vagina. Failure → uterine/apical prolapse and, after hysterectomy, vaginal vault prolapse and enterocele.
- Level II — lateral attachment: the mid-vagina is attached laterally to the arcus tendineus fascia pelvis ("white line") and the levator fascia. Failure → anterior (cystocele) and posterior (rectocele) wall prolapse.
- Level III — distal fusion: the lower vagina is fused to the perineal body, urethra and levators. Failure → urethrocele and perineal descent/deficiency.