Endometriosis or IBS? Why bowel symptoms send women down the wrong path
Bloating, pain and altered bowel habit fit both diagnoses. The cyclical pattern is what separates them, and it is the question rarely asked.
A large number of women with endometriosis are told they have irritable bowel syndrome first. The symptoms genuinely overlap, and the differentiating question - does this track with your cycle? - is often not asked.
In short: Endometriosis and IBS both cause bloating, abdominal pain and altered bowel habit. The distinguishing feature is timing: endometriosis symptoms typically worsen in a cyclical pattern around menstruation, and are usually accompanied by severe period pain or pain during sex.
What overlaps
- Bloating, sometimes dramatic
- Cramping abdominal pain
- Constipation, diarrhoea, or alternating
- Pain on opening the bowels
- Nausea and fatigue
What points towards endometriosis
- Symptoms clearly worse in the days before and during your period
- Severe period pain alongside the bowel symptoms
- Deep pain during or after sex
- Pain on opening the bowels specifically around menstruation
- Blood in the stool around your period, which needs prompt
- Shoulder-tip pain, which can occur with diaphragmatic involvement
What points towards IBS
- Symptoms unrelated to cycle timing
- A clear relationship with specific foods, stress or meal patterns
- Relief after opening the bowels
- Absence of gynaecological symptoms
They can also co-exist, which is why an IBS diagnosis does not close the question.
What to ask for
Take a diary showing bowel symptoms alongside cycle days for two or three months. Ask specifically: "Could this be endometriosis? My bowel symptoms follow my cycle." Reasonable next steps include coeliac and a faecal calprotectin test to exclude inflammatory bowel disease, alongside gynaecological assessment.
Why the delay matters
Years spent on low-FODMAP diets and antispasmodics is time not spent treating the underlying condition, and it teaches women that their symptoms are a food problem they are failing to control.
Common questions
Can a colonoscopy detect endometriosis? Usually not. Bowel endometriosis often sits on the outer surface, not inside the bowel.
Can I have both? Yes, and it is common.
Does the low-FODMAP diet help? It can reduce bloating in both, which is why symptom improvement on it does not confirm IBS.
Read the full endometriosis guide or the symptom checklist.