Constipation affects an overwhelming proportion of people with endometriosis. In one study of endometriosis patients who reported bowel symptoms, roughly nine out of ten had constipation, making it the single most common gastrointestinal complaint in the group. Yet constipation in this context is frequently dismissed as a standalone digestive issue or lumped in with irritable bowel syndrome, delaying proper treatment for years. The relationship between the two conditions runs deeper than coincidence, involving everything from tissue invasion and adhesions to pelvic floor muscle dysfunction and hormone-driven changes in gut motility.
How Common Is Constipation in Endometriosis
Studies consistently place constipation among the top bowel complaints for people with endometriosis. A recent study of patients with endometriosis and bowel symptoms found constipation in 91% of participants and irritable bowel syndrome in 65%, with significant overlap between the two.1Continence. Functional Defecatory Disorders Are Common in Patients with Endometriosis and Bowel Symptoms That number is striking, and while it comes from a group already reporting bowel problems rather than from all endometriosis patients, it illustrates how dominant constipation is among the gastrointestinal symptoms that endometriosis produces. Even in broader samples that include patients without specific bowel complaints, constipation, bloating, and difficulty evacuating stool appear far more often than in the general population.
Part of the reason these numbers are hard to pin down precisely is that many people with endometriosis spend years seeing gastroenterologists before anyone considers a gynecological cause. One study tracking patients who eventually received an endometriosis diagnosis found that some had been referred through gastroenterology clinics for years, and a subset turned out to have significant narrowing of the rectosigmoid colon from endometriotic lesions, requiring surgery.2PubMed. Irritable bowel syndrome and chronic constipation in patients with endometriosis These patients had been living with constipation that had a clear physical explanation but was being managed as a functional gut problem.
Why Endometriosis Causes Constipation
There is no single mechanism. Constipation in endometriosis can result from direct tissue invasion, from the body’s pain response altering pelvic muscle function, from hormonal effects on gut motility, and from changes in the gut microbiome. In most patients, several of these pathways are probably operating at once, which is part of why constipation in this population can be so stubborn to treat.
Physical Obstruction and Adhesions
Endometriosis can grow on or into the walls of the intestine, particularly the rectum and sigmoid colon. When tissue infiltrates the bowel wall, it can narrow the passage that stool moves through. A comprehensive review of endometriosis-related intestinal obstruction found that the mechanisms include masses growing within the bowel wall or its lining, external compression of the bowel, adhesions binding loops of intestine together, and even intussusception, where one segment of bowel telescopes into another.3PubMed Central. Endometriosis as an Uncommon Cause of Intestinal Obstruction—A Comprehensive Literature Review Full obstruction is uncommon, but partial obstruction and adhesion-related slowing of bowel transit are far more frequent and contribute directly to constipation.
Pelvic Floor Muscle Dysfunction
This is arguably the most underappreciated pathway. Chronic pelvic pain from endometriosis causes the pelvic floor muscles to tighten in a protective guarding response. Over time, these muscles can become hypertonic, meaning they stay contracted even when they should relax. During a bowel movement, the pelvic floor needs to relax to let stool pass. When it cannot, the result is straining, incomplete evacuation, a sense of blockage, and constipation. Researchers describe this as a “nonrelaxing pelvic floor” and note that cross-sensitization of pelvic floor muscles contributes to a chronic guarding state that worsens constipation over time.4Scientific Archives. The Consideration of Endometriosis in Women with Persistent Gastrointestinal Symptoms and a Novel Neuromusculoskeletal Treatment Approach
Imaging studies confirm this. Using transperineal ultrasound, researchers found that women with both endometriosis and chronic constipation showed signs of pelvic floor muscle hypertonia: less opening of the pelvic floor during straining, and more involuntary co-contraction of the muscles that should be releasing. These findings were more pronounced in women with ovarian endometriosis specifically, suggesting the location of endometriotic lesions influences how severely the pelvic floor responds.5PubMed. Pelvic floor dysfunction at transperineal ultrasound and chronic constipation in women with endometriosis
Hormonal Effects on Gut Motility
Hormones tied to the reproductive cycle also play a role. Laboratory studies have shown that progesterone, luteinizing hormone, and relaxin act as antagonists to the nerves that drive gut motility, essentially slowing the muscular contractions that push food and waste through the intestines.6Karger. Relationship of Reproductive Hormones and Neuromuscular Disease of the Gastrointestinal Tract This helps explain why many people with endometriosis notice their constipation worsens during certain phases of their menstrual cycle, particularly the luteal phase when progesterone is highest. Endometriosis also creates its own local hormonal environment, with lesions producing estrogen and triggering inflammatory cascades that may further disrupt normal bowel function.
Gut Microbiome Disruption
There is growing evidence that the gut microbiome is altered in endometriosis. The relationship likely runs in both directions: dysbiosis may contribute to the immune dysfunction that allows endometriosis to develop, and endometriosis-related inflammation may change the gut bacterial landscape. Research has linked this disruption to impaired immune function, elevated inflammatory signaling, and altered estrogen metabolism, all of which could worsen bowel symptoms.7PubMed Central. Endometriosis and dysbiosis: State of art The microbiome angle is still early-stage science, but it may help explain why some endometriosis patients respond to dietary interventions that reshape gut bacteria.
Why It Gets Mistaken for IBS
The symptom overlap between endometriosis-related bowel problems and irritable bowel syndrome is enormous. Bloating, cramping, alternating constipation and diarrhea, incomplete evacuation: all of these appear in both conditions. Because IBS is diagnosed based on symptoms rather than a specific test, and because endometriosis is notoriously difficult to diagnose without imaging or surgery, many people receive an IBS label years before their endometriosis is identified. The diagnostic delay for endometriosis averages somewhere around seven to ten years in most countries, and during that time, pre-diagnosis healthcare costs climb substantially. One study found that patients with longer diagnostic delays accumulated significantly higher healthcare costs in the years before diagnosis, with those experiencing the longest delays averaging over $34,000 in annual all-cause healthcare spending compared to about $21,500 for those diagnosed more quickly.8PubMed Central. Impact of Endometriosis Diagnostic Delays on Healthcare Resource Utilization and Costs
There are some clues that constipation might be endometriosis-related rather than garden-variety IBS. Cyclical worsening that tracks with the menstrual period is a red flag. Pain with bowel movements, especially deep rectal pain, is more suggestive of endometriosis than typical IBS. And constipation that does not respond to standard IBS treatments, like fiber supplementation and osmotic laxatives, deserves further investigation. None of these are definitive on their own, but when several appear together, pushing for a specialist evaluation is reasonable.
Why Standard Hormonal Treatments Often Miss Constipation
Hormonal therapies like combined oral contraceptives and progestin-only medications are first-line treatments for endometriosis pain. They suppress the hormonal fluctuations that drive endometriotic lesion growth. But when it comes to constipation specifically, the evidence is disappointing. A case-cohort study tracking gastrointestinal symptoms before and after starting hormonal therapy found that neither combined oral contraceptives nor progesterone had any measurable effect on gut symptoms when patients were followed over time.9PubMed Central. Gastrointestinal symptoms among endometriosis patients–A case-cohort study A comprehensive literature review on medical treatment for deep endometriosis affecting the rectum and sigmoid colon echoed this, finding that patients with irritative-type symptoms like diarrhea and urgency appeared to respond better to medical therapy than those with constipation.10PubMed. Medical treatment in the management of deep endometriosis infiltrating the proximal rectum and sigmoid colon: a comprehensive literature review
This makes sense when you consider the mechanisms described earlier. If constipation is being driven by pelvic floor dysfunction, adhesions, or physical narrowing of the bowel, suppressing hormones will not fix those problems. The hormonal environment contributes to motility changes, but by the time a patient has developed chronic constipation from endometriosis, there are usually multiple factors at work that hormonal therapy alone cannot undo.
Dietary Approaches and the Low-FODMAP Diet
Given the limitations of hormonal therapy for bowel symptoms, dietary strategies have received increasing attention. The low-FODMAP diet, originally developed for IBS, restricts certain fermentable carbohydrates that draw water into the intestine and feed gas-producing bacteria. For endometriosis patients with constipation, the results have been encouraging. A prospective cohort study found that constipation scores improved significantly after following a low-FODMAP diet, with a mean improvement of about 2 points on a standardized constipation scale.11PubMed Central. Effects of a low-FODMAP diet on patients with endometriosis, a prospective cohort study
Stronger evidence came from a randomized controlled crossover trial, where participants ate either a low-FODMAP diet or a nutritionally matched control diet for 28 days. Sixty percent of women responded to the low-FODMAP diet compared with 26% on the control diet. Overall symptom scores were markedly lower on the low-FODMAP diet, and improvements extended to abdominal pain, bloating, stool form, and quality of life.12PubMed Central. Clinical Trial: Effect of a 28-Day Low FODMAP Diet on Gastrointestinal Symptoms Associated With Endometriosis (EndoFOD)-A Randomised, Controlled Crossover Feeding Study A systematic review of the available studies concluded that a low-FODMAP diet can reduce gastrointestinal symptoms in endometriosis patients, particularly those with abdominal pain, bloating, constipation, or IBS-like symptoms, though it noted the evidence base is still small and recommended the diet be followed with guidance from a dietitian.13PubMed Central. Low-FODMAP Diet for Gastrointestinal Symptoms in Endometriosis: A Systematic Review
The low-FODMAP diet is not a cure for the underlying disease, and it requires careful management to avoid nutritional deficiencies during the elimination phase. But for someone whose constipation is not resolving with other treatments, it represents one of the better-supported non-surgical options.
What Surgery Can and Cannot Fix
For deep infiltrating endometriosis affecting the rectum or sigmoid colon, surgery is sometimes the most direct solution. Removing lesions that are physically obstructing or compressing the bowel can restore normal anatomy. But the relationship between surgery and constipation is complicated. Research has found that while surgery often produces significant improvement in pelvic pain and overall well-being, digestive complaints like constipation may be incompletely cured. Some patients even develop new bowel symptoms after surgery that were not present before.14PubMed. Bowel dysfunction before and after surgery for endometriosis
Data from a randomized trial found that patients who had severe constipation before surgery were less likely to achieve normal bowel function afterward, regardless of whether the surgical approach was radical or conservative.15PubMed. Baseline severe constipation negatively impacts functional outcomes of surgery for deep endometriosis infiltrating the rectum: Results of the ENDORE randomized trial In other words, the longer constipation has been entrenched and the more severe it is, the less likely surgery alone is to resolve it. This probably reflects the contribution of pelvic floor dysfunction and nerve sensitization that develop alongside the structural disease. Removing a lesion does not automatically reprogram muscles that have spent years in a guarding state.
Surgical technique matters, though. Nerve-sparing approaches, which aim to preserve the autonomic nerve fibers that control bowel function, have shown promising results. One study found that gastrointestinal function scores improved significantly after vascular- and nerve-sparing bowel resection.16PubMed. Vascular- and nerve-sparing bowel resection for deep endometriosis: A retrospective single-center study Another found that after nerve-sparing segmental bowel resection, only about 4% of patients reported severe constipation at an average follow-up of nearly three years, and patients typically recovered bowel function within one day of surgery.17European Journal of Obstetrics & Gynecology and Reproductive Biology. Mesenteric vascular and nerve sparing surgery in laparoscopic segmental intestinal resection for deep infiltrating endometriosis Constipation risk in that study was related to how close the surgical site was to the anal opening and how much time had passed since the operation, which are consistent with nerve recovery patterns.
Transanal Irrigation for Persistent Bowel Problems
For patients whose constipation persists after medical or surgical treatment, transanal irrigation is an underused option. The technique involves flushing water into the rectum to help clear stool, essentially bypassing the dysfunction in the muscles and nerves that are supposed to move things along. A retrospective study of endometriosis patients using transanal irrigation found a meaningful increase in patient satisfaction and a reduction in pain scores, as well as a significant improvement in bowel symptom severity scores.18PubMed Central. Use of transanal irrigation (TAI) in the treatment of persistent bowel disorders in patients with endometriosis: A retrospective study It is not glamorous, and it is rarely the first thing a clinician suggests, but for people stuck in a cycle of straining, incomplete evacuation, and bloating, it can make a tangible difference in daily life.
Opioid-Induced Constipation as a Compounding Factor
There is a cruel irony in how pain management for endometriosis can make constipation worse. Opioid medications are known to slow gut motility, and endometriosis patients are prescribed opioids at higher rates than the general population. Among chronic opioid users with endometriosis, constipation was the most commonly reported side effect, affecting about a third of patients over a two-year follow-up period.19PubMed Central. Chronic opioid use and complication risks in women with endometriosis: A cohort study in US administrative claims When someone already has constipation from endometriosis itself and then develops additional constipation from pain medication, the combined effect can be debilitating. Anyone managing endometriosis pain with opioids should be proactive about bowel management from the start, rather than waiting for constipation to become established.
Complementary Therapies and Pelvic Floor Rehabilitation
Given the role of pelvic floor dysfunction in endometriosis-related constipation, pelvic floor physical therapy is one of the more logical interventions, though it is still underutilized. A systematic review of holistic approaches to endometriosis symptom management found that physical therapy, manual therapy, acupuncture, dietary changes, and cognitive behavioral therapy all showed symptom reduction with no negative side effects.20PubMed Central. Holistic Approaches in Endometriosis – as an Effective Method of Supporting Traditional Treatment: A Systematic Search and Narrative Review Most of that research focused on pain and quality of life rather than constipation specifically, so the direct evidence for constipation relief is thinner. A narrative review of complementary treatments echoed the promise but cautioned that isolating the effect of any single therapy is difficult because studies tend to involve multiple concurrent interventions.21PubMed Central. Hormonal and complimentary treatments for endometriosis: a narrative review
Still, the logic is straightforward. If a nonrelaxing pelvic floor is contributing to constipation, then teaching those muscles to relax through manual therapy and biofeedback should help. Many pelvic floor therapists work specifically with endometriosis patients, and the combination of down-training exercises, internal manual release, and breathing techniques can address both the pain and the bowel dysfunction that stem from the same muscular tension. For patients whose constipation does not respond to dietary changes or hormonal therapy, pelvic floor rehabilitation is worth pursuing before assuming surgery is the only remaining option.
When Constipation Should Prompt an Endometriosis Workup
Not every person with constipation has endometriosis. But certain patterns warrant a closer look. Constipation that worsens predictably around the menstrual period, constipation paired with deep pelvic or rectal pain during bowel movements, and constipation that fails to improve with standard dietary and laxative interventions, especially in someone of reproductive age with other symptoms like painful periods or pain during intercourse, should raise the question. Rectal bleeding during menstruation, though less common, is another signal that endometriotic tissue may be involving the bowel directly.
The challenge is that no single screening tool reliably separates endometriosis-related constipation from other causes based on symptoms alone. Imaging with transvaginal ultrasound by an experienced operator, or MRI of the pelvis, can detect deep infiltrating endometriosis that affects the bowel, but these are not routinely ordered for someone presenting with constipation to a primary care doctor or gastroenterologist. Advocacy from the patient, and willingness from the clinician to look beyond the digestive system, often makes the difference between years of mismanaged IBS treatment and an accurate diagnosis that opens the door to more targeted care.