When IBS Isn’t the Whole Story What Endometriosis Patients Need GI Doctors to See

For many endometriosis patients, the story goes something like this: your abdomen suddenly swells to the point where clothes don’t fit, your bowels stop moving for days or swing unpredictably, and when they do, the stool looks thin, strained, or incomplete. You finally say something out loud — and you’re told it’s IBS (Irritable Bowel Syndrome)

Sometimes that diagnosis brings relief. At least it has a name. But often, it doesn’t explain why the symptoms feel so intense, so cyclical, or so different from anything you’ve experienced before. And it doesn’t explain why bloating feels painful, unusual inflammation, not just an uncomfortable feeling.

What many people don’t realize is that endometriosis and your gastrointestinal system are deeply connected. The gut doesn’t exist in isolation. It sits inside an inflammatory pelvic environment, shares nerve pathways with reproductive organs, responds to hormonal shifts, and is influenced by pain patterns that change how the body moves and protects itself. When endometriosis is present, bowel symptoms can look identical to IBS — but the driver underneath may be very different.

“Endo belly,” for example, is often dismissed as gas or dietary intolerance. But for many patients, it’s a sudden inflammatory swelling that comes with pressure, heaviness, and a sense that the abdomen is tight or reactive. This can be driven by inflammatory mediators associated with endometriosis, changes in vascular permeability, altered gut sensitivity, and nervous system activation. It is not simply about what you eat it’s about how your body is responding.

Severe constipation for endometriosis patients is also frequently misunderstood. It’s easy to assume fiber is the solution, but many patients discover that more fiber only makes things worse. That’s because constipation in this context isn’t always about stool bulk. It’s often about coordination. Chronic pelvic pain can cause the pelvic floor muscles to tighten defensively, making it difficult for stool to pass even when it’s soft. Hormonal fluctuations and inflammation can slow gut motility. In some cases, deep endometriosis or adhesions near the bowel can interfere with how the rectum and sigmoid colon function, especially during certain points in the menstrual cycle.

Then there’s pencil-thin stool — one of the most anxiety-provoking symptoms patients hesitate to mention. While this can sometimes be related to functional bowel spasm, it should never be brushed off without context. A change in stool caliber that is new, persistent, or cyclical deserves a closer look, particularly when paired with pelvic pain, incomplete evacuation, or worsening constipation. What matters isn’t a single episode, but the pattern over time and how it fits into the larger clinical picture.

This is where the IBS label can become limiting. IBS is a real diagnosis, but it’s a diagnosis based on symptoms rather than cause. In endometriosis patients, those symptoms may be the downstream expression of pelvic inflammation, altered nerve signaling, hormonal effects on motility, or pelvic floor dysfunction. Studies consistently show a high overlap between endometriosis and IBS-type symptoms, which helps explain why so many patients are diagnosed with IBS years before their endometriosis is ever recognized.

The goal isn’t to argue with a gastroenterologist or dismiss their expertise. It is time to widen the lens. If bowel symptoms worsen around ovulation or before a period, if bloating feels inflammatory rather than food-related, if constipation feels like something isn’t relaxing rather than something isn’t moving — those are important clues. Those signs suggest that the gut may be responding to what’s happening in the pelvis, not acting alone.

When speaking with a GI doctor, framing matters. 

Instead of trying to self-diagnose, it’s often more effective to describe patterns. Talking about cyclical flares, pelvic pressure, pain with bowel movements, or a sense of incomplete emptying helps shift the conversation. Asking whether pelvic floor dysfunction or endometriosis-related factors could be contributing opens the door to collaboration rather than confrontation. Even when colonoscopy findings are normal, that doesn’t mean the story ends there. Pelvic causes don’t always show up on standard GI testing.

Women with endometriosis aren’t imagining their symptoms, and it’s not that they’re failing at IBS management. In many cases, their bodies are responding to a complex pelvic condition that deserves coordinated care. When gastroenterology and gynecology start working in collaborative ways, patients finally start getting answers that make sense.

You are not wrong, you need to have all your symptoms heard and discussed.  You deserve a care team willing to ask better questions — and to listen when your body tells a story that doesn’t quite fit inside the IBS box.

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References

1. European Society of Human Reproduction and Embryology (ESHRE). Endometriosis: Guideline and Management Recommendations.

2. American College of Gastroenterology. Clinical Guideline: Management of Irritable Bowel Syndrome.

3. Rome Foundation. Rome IV Criteria for Disorders of Gut–Brain Interaction.

4. Seaman HE, et al. Endometriosis and Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis. Human Reproduction Update.