Uterine prolapse happens when the muscles and ligaments holding the uterus in place weaken enough that it drops downward into the vaginal canal. It affects up to 50% of women who have given birth, with the majority of cases occurring after age 60. The causes range from the physical trauma of childbirth to the gradual loss of estrogen after menopause, and several factors often overlap.
How the Uterus Stays in Place
The uterus is held in position by a hammock-like layer of muscles and connective tissue called the pelvic floor. The largest of these muscles, the levator ani, wraps around the entire pelvis and provides most of the structural support. Two sets of ligaments, the cardinal ligaments on each side and the uterosacral ligaments at the back, anchor the uterus to the pelvic bones. When any combination of these muscles and ligaments stretches, tears, or thins out, the uterus loses its support and begins to descend under the force of gravity and everyday abdominal pressure.
Vaginal Childbirth Is the Strongest Risk Factor
Vaginal delivery puts enormous strain on the pelvic floor. The levator ani muscle can stretch to several times its resting length during labor, and in some deliveries it tears partially or fully. Forceps-assisted delivery carries roughly seven times the odds of a significant muscle tear compared to a normal vaginal birth, and about four and a half times the odds compared to vacuum-assisted delivery. Each additional vaginal birth compounds the damage, which is why prolapse risk rises with the number of deliveries.
Prolonged labor, pushing for extended periods, and delivering a large baby all increase the mechanical stress on these tissues. The damage may not cause symptoms right away. Many women live with weakened pelvic floor muscles for decades before prolapse becomes noticeable, usually after menopause accelerates the tissue changes.
Estrogen Loss After Menopause
Estrogen plays a direct role in keeping pelvic tissues strong. It stimulates the production of collagen and elastin, the two proteins that give ligaments and connective tissue their firmness and stretch. After menopause, estrogen levels drop sharply, and the body produces fewer of the enzymes needed to build and maintain these proteins. At the same time, enzymes that break down collagen become more active.
The result is a gradual thinning and weakening of the ligaments, vaginal walls, and muscle attachments that hold pelvic organs in place. This is why uterine prolapse is overwhelmingly a condition of older women. Research on estrogen therapy in postmenopausal women with prolapse has shown that it can boost collagen and elastin production and slow tissue breakdown, confirming that estrogen deficiency is a central driver of the problem rather than just a coincidence of aging.
Chronic Pressure on the Pelvic Floor
Anything that repeatedly pushes downward on the pelvic floor can gradually stretch and weaken its support structures. The most common culprits are obesity, chronic cough, chronic constipation, and repeated heavy lifting. These conditions all increase intra-abdominal pressure, which transfers directly to the pelvic floor with every cough, strain, or physical effort.
Obesity is particularly well studied. Women who are obese have roughly three times the odds of their prolapse worsening by a clinically meaningful amount within a single year compared to women at a healthy weight. Chronic lung conditions like COPD cause repeated forceful coughing that hammers the pelvic floor thousands of times a day. Chronic constipation means years of straining during bowel movements, which creates the same kind of downward force. Even occupations that involve regular heavy lifting can contribute over time.
Genetics and Connective Tissue Disorders
Some women are born with weaker connective tissue, which makes prolapse more likely regardless of other risk factors. Ehlers-Danlos syndrome (EDS) is a hereditary condition that disrupts collagen production throughout the body. Women with EDS can develop pelvic organ prolapse as early as their late 20s, without ever having been pregnant or gone through menopause. Other connective tissue disorders, including Marfan syndrome, carry similar risks.
Even without a diagnosed disorder, there appears to be a genetic component. Women whose mothers or sisters have had prolapse are at higher risk, likely because of inherited variations in collagen quality and quantity. If you’ve noticed prolapse symptoms at a younger age than expected, a connective tissue condition is worth discussing with your provider.
Previous Hysterectomy
Removing the uterus doesn’t eliminate prolapse risk. The top of the vagina (called the vault) can drop downward after a hysterectomy if the supporting ligaments aren’t adequately reattached during surgery or if they weaken over time. This is called vault prolapse, and it occurs after roughly 12% of hysterectomies that were performed because of existing prolapse, and about 2% of hysterectomies done for other reasons. A large study from Austria estimated that 6% to 8% of post-hysterectomy vault prolapse cases eventually need surgical repair.
How Prolapse Is Graded
Doctors classify prolapse severity using a standardized system that measures how far the uterus (or vaginal vault) has descended relative to the vaginal opening:
- Stage I: The uterus has dropped but remains more than 1 cm above the vaginal opening. Many women at this stage have no symptoms.
- Stage II: The lowest point of descent is within 1 cm above or below the vaginal opening. This is often when symptoms like pressure or a bulging sensation begin.
- Stage III: The uterus protrudes more than 1 cm beyond the vaginal opening but hasn’t fully descended.
- Stage IV: Complete eversion, meaning the uterus and vaginal walls have fully turned inside out and descended outside the body.
Staging helps guide treatment decisions, but symptoms don’t always match the grade. Some women with Stage II prolapse feel significant discomfort, while others with Stage III have adapted and notice relatively little disruption to daily life.
Why Multiple Factors Usually Overlap
Uterine prolapse rarely has a single cause. The typical pattern involves childbirth damage that weakens the pelvic floor decades before symptoms appear, followed by estrogen loss after menopause that accelerates tissue breakdown. Layer on chronic constipation, extra body weight, or a genetic predisposition toward weaker collagen, and the cumulative effect crosses the threshold where the uterus begins to descend. Understanding which factors apply to you can help focus treatment and prevention strategies, whether that means pelvic floor strengthening exercises, managing chronic cough, addressing constipation, or considering hormonal support for tissue health.