Vaginal prolapse happens when the muscles, ligaments, and connective tissue that hold the vagina in place weaken enough that the vaginal walls (and sometimes nearby organs like the bladder or rectum) slip downward. The single biggest cause is vaginal childbirth, but it’s rarely just one thing. Prolapse typically results from a combination of factors that accumulate over years, including hormonal changes, genetics, body weight, and anything that puts chronic pressure on the pelvic floor.
How the Vagina Stays in Place
Understanding what fails helps explain why it fails. The vagina is held in position by a hammock-like system of muscles and ligaments working together. The levator ani, a broad muscle group lining the bottom of the pelvis, forms a horizontal shelf that supports the rectum and the upper two-thirds of the vagina. When this muscle is intact, it keeps a narrow opening (called the urogenital hiatus) pulled tight. If the levator ani weakens or loosens, that opening widens, and the organs sitting above it can start to descend.
Above the muscle layer, two sets of ligaments anchor the upper vagina and cervix. The cardinal ligaments connect the cervix and upper vagina to the side walls of the pelvis. The uterosacral ligaments run from the cervix to the front of the sacrum. Together, these ligaments hold the uterus and upper vagina in position over the muscular shelf below. Prolapse occurs when damage or deterioration hits the muscles, the ligaments, or both.
Vaginal Childbirth Is the Strongest Risk Factor
A single vaginal delivery increases the odds of prolapse by roughly tenfold compared to never giving birth. That number comes from a study that controlled for other variables and still found an odds ratio of 9.73 for women with one vaginal birth versus none. What’s surprising is that additional vaginal births after the first don’t substantially raise the risk further. Each extra delivery added only a negligible increase in odds.
Cesarean delivery, by contrast, was not associated with a meaningful increase in prolapse risk. Women who had only cesarean births had similar odds to women who had never given birth at all. This points to the physical process of vaginal delivery itself as the damaging event: the baby’s head stretching and sometimes tearing the levator ani muscle, the connective tissue, and the nerves that control pelvic floor function. The damage may not cause noticeable prolapse for years or even decades, but it creates a structural vulnerability that worsens with aging.
Menopause and Estrogen Loss
Estrogen plays a direct role in maintaining the strength of vaginal and pelvic tissue. It helps regulate collagen production, particularly collagen type I, which forms the dense, well-organized fibers that give ligaments their tensile strength. After menopause, collagen metabolism shifts toward breakdown rather than building. The ratio of strong, organized collagen to weaker, less-structured types decreases in the pelvic connective tissue of postmenopausal women not taking hormone replacement therapy.
This isn’t a subtle biochemical footnote. The practical result is that the vaginal walls become thinner and less elastic, and the ligaments holding everything up gradually lose their ability to resist downward force. This is why many women first notice prolapse symptoms in the years following menopause, even if the underlying damage happened during childbirth decades earlier. The hormonal shift essentially removes the body’s ability to maintain and repair the tissue that was already compromised.
Chronic Pressure on the Pelvic Floor
Anything that repeatedly pushes down on the pelvic organs from above can accelerate prolapse. A 2023 systematic review and meta-analysis quantified several of these risk factors:
- Obesity: A BMI over 30 increased prolapse risk by 44 percent. The extra abdominal weight creates constant downward pressure on the pelvic floor, essentially making the muscles and ligaments work harder every hour of every day.
- Chronic cough: Persistent coughing, whether from smoking, asthma, or chronic lung disease, increased risk by 52 percent. Each cough generates a sharp spike of pressure in the abdomen that pushes directly against the pelvic floor.
- Occupational strain: Jobs involving heavy lifting or prolonged standing were associated with an 86 percent increase in risk. Repeated heavy lifting creates the same kind of pressure spikes as coughing, but often sustained over years of work.
Chronic constipation and straining during bowel movements work through the same mechanism. The repeated bearing-down effort forces the pelvic organs downward and stretches the supporting tissue over time.
Genetics and Connective Tissue Disorders
Some women are born with connective tissue that is inherently less strong. The most well-known example is Ehlers-Danlos syndrome, a group of inherited conditions caused by defects in the genes that produce collagen types I, III, and V. These are the exact collagen types responsible for giving soft tissues their strength. Women with Ehlers-Danlos have a higher risk of developing prolapse, often at younger ages than typical.
You don’t need a diagnosed connective tissue disorder to have a genetic predisposition, though. Researchers have identified specific gene variants that increase prolapse risk in the general population. One is a variation in the COL3A1 gene, which codes for type III collagen. Another is a polymorphism in the COL1A1 gene that affects type I collagen. In general, women whose connective tissue has a higher proportion of weaker collagen types (III and V) relative to the stronger type I have tissue that stretches more easily and is less able to support pelvic organs over time. If your mother or sisters have dealt with prolapse, your own risk is likely elevated.
Prolapse After Hysterectomy
Having the uterus removed doesn’t eliminate the possibility of prolapse. The top of the remaining vaginal canal (called the vaginal vault) can descend if the supporting ligaments are already weakened. This is relatively uncommon, occurring in about 0.5 percent of women who’ve had a hysterectomy, but it does happen. The cause isn’t the surgery itself so much as pre-existing weakness in the pelvic tissues that was already present before the hysterectomy. Women who had a hysterectomy because of prolapse or who already had lax pelvic tissue are at highest risk.
How Severity Is Measured
Doctors grade prolapse on a five-stage scale based on how far the tissue has descended relative to the vaginal opening. At Stage 0, there’s no prolapse at all. Stage 1 means the tissue has shifted but remains well above the vaginal opening. At Stage 2, the lowest point of the prolapse is within about a centimeter of the opening in either direction. Stage 3 means tissue protrudes beyond the opening but the vagina hasn’t completely turned inside out. Stage 4, the most severe, is essentially complete eversion, where the vaginal walls have fully descended.
Many women live with Stage 1 or 2 prolapse without significant symptoms. Prolapse often becomes noticeable when it reaches Stage 2 or beyond, producing a sensation of pressure, heaviness, or a visible bulge. The stage matters because it guides treatment decisions, from pelvic floor exercises and pessaries for milder cases to surgical repair for more advanced ones.
Why It’s Usually Multiple Factors
Prolapse is best understood as a threshold problem. Your pelvic floor can absorb a certain amount of damage and still function. But when enough risk factors stack up, the system fails. A woman who had two vaginal deliveries in her thirties, gained weight in her forties, went through menopause at fifty, and has a genetic tendency toward weaker collagen may cross that threshold in her sixties. Another woman with only one of those risk factors may never develop noticeable prolapse. The combination and accumulation of causes over a lifetime is what ultimately determines whether and when symptoms appear.