Endometriosis or IBS? How to Tell the Difference

Colette Kirk
Aug 3
5 min read

Updated: 5 days ago

Bloating. Abdominal pain. Constipation. Diarrhoea.

If you live with digestive symptoms, it can be difficult to know what's causing them.

For many women, symptoms are attributed to either endometriosis or irritable bowel syndrome (IBS). The challenge is that these two conditions share many of the same symptoms and, importantly, they can occur at the same time.

In fact, research suggests that people with endometriosis are around three times more likely to have IBS than those without endometriosis. This means that digestive symptoms are not always caused by endometriosis alone.

Understanding the differences between these conditions can help you have more informed conversations with your healthcare team and ensure your symptoms are properly assessed.

What is endometriosis?

Endometriosis is a chronic condition where tissue similar to the lining of the uterus grows outside the womb. These deposits are most commonly found within the pelvis but can also affect nearby organs, including the bowel and bladder.

Symptoms vary from person to person but often include pelvic pain, painful periods, pain during or after sex, fatigue and fertility difficulties.

Digestive symptoms are also common.

What is IBS?

Irritable bowel syndrome (IBS) is a disorder of gut–brain interaction. It affects how the digestive system functions rather than causing damage to the bowel itself.

People with IBS commonly experience:

Abdominal pain
Bloating
Constipation
Diarrhoea
Changes in bowel habits

Symptoms often come and go over time and may fluctuate with stress, diet or hormonal changes.

What is IBS?

Why are they often confused?

Endometriosis and IBS share many of the same symptoms.

Both conditions may cause:

Bloating
Abdominal pain
Constipation
Diarrhoea
Feeling that the bowel hasn't emptied properly
Reduced quality of life

Because these symptoms overlap, it isn't always possible to tell which condition is responsible based on symptoms alone.

In some cases, both conditions are contributing.

Endometriosis vs IBS: Symptom comparison

Symptom	More common in IBS	More common in endometriosis
Bloating	✓	✓
Abdominal pain	✓	✓
Constipation	✓	✓
Diarrhoea	✓	✓
Symptoms linked to bowel movements	✓	Sometimes
Pain that worsens during periods	Sometimes	✓
Pelvic pain outside the bowel	Sometimes	✓
Pain during or after sex	Rare	✓
Heavy or painful periods	No	✓
Difficulty becoming pregnant	No	✓

Although this table highlights common patterns, everyone's experience is different. Symptoms alone cannot confirm a diagnosis.

Clues that symptoms may be related to IBS

IBS may be more likely if:

Your abdominal pain is related to opening your bowels.
Your symptoms improve or worsen after a bowel movement.
You experience ongoing constipation, diarrhoea or both.
Your bowel habits fluctuate over time.
Your symptoms meet the Rome IV diagnostic criteria for IBS.

IBS symptoms can still become worse around your menstrual cycle, so this doesn't necessarily rule out IBS.

Clues that symptoms may be related to endometriosis

Endometriosis may be more likely if:

Pain is closely linked to your menstrual cycle.
You have severe period pain.
You experience pain during or after sex.
You have chronic pelvic pain.
You have difficulty becoming pregnant.
Your symptoms have not improved despite treatment for IBS.

Some people with bowel endometriosis may also experience painful bowel movements, particularly during menstruation.

Can you have both IBS and endometriosis?

Yes. In fact, this is much more common than many people realise.

A systematic review and meta-analysis involving more than 96,000 participants found that people with endometriosis were around three times more likely to have IBS compared with those without endometriosis. Around one in four women with endometriosis also had IBS.

This is important because it means digestive symptoms shouldn't automatically be attributed to endometriosis alone.

Recognising that IBS may also be present can help people access more targeted support for their digestive symptoms.

How are these conditions diagnosed?

There is no single blood test that diagnoses either condition.

IBS

IBS is diagnosed based on your symptoms, medical history and by excluding other conditions where appropriate. Healthcare professionals commonly use the Rome IV criteria alongside an assessment for any "red flag" symptoms that might suggest another diagnosis.

Endometriosis

Diagnosing endometriosis can take time because symptoms vary widely and overlap with other conditions.

Diagnosis may involve:

A discussion of your symptoms and menstrual history.
A pelvic examination where appropriate.
Ultrasound or MRI in some cases.
Referral to a gynaecologist.
Laparoscopy may still be required in selected cases, although advances in imaging mean not everyone requires surgery to confirm the diagnosis.

When should you seek medical advice?

Speak to your GP or healthcare professional if you have:

Persistent abdominal pain
Ongoing bloating
Changes in your bowel habits
Blood in your stool
Unexplained weight loss
Symptoms that are affecting your daily life or quality of life

Although IBS and endometriosis are common, it's important not to self-diagnose. Other digestive conditions, including coeliac disease, inflammatory bowel disease and colorectal disease, may also need to be considered depending on your symptoms.

Can diet help?

Diet can be an important part of managing IBS symptoms, but there is no single diet that is recommended for everyone with endometriosis or IBS.

The best approach depends on:

Your diagnosis
Your symptoms
Whether one or both conditions are contributing
Your nutritional needs
Your overall health

Restrictive diets are not always necessary and, in some cases, may do more harm than good.

Working with a specialist dietitian can help you identify strategies that are evidence-based, practical and tailored to your individual symptoms.

Key takeaways

Endometriosis and IBS share many of the same symptoms.
It isn't always possible to tell the difference based on symptoms alone.
People with endometriosis are around three times more likely to have IBS.
Around one in four women with endometriosis also have IBS.
Digestive symptoms deserve proper assessment and shouldn't automatically be attributed to endometriosis.
An accurate diagnosis is the first step towards finding the most appropriate treatment and nutrition support.

How CK Clinical Nutrition can help

If you're living with persistent digestive symptoms alongside endometriosis, it can be difficult to know what's causing them or where to start.

As an HCPC Registered Dietitian, Lead Specialist NHS Dietitian and Clinical Nutrition Researcher, Dr Colette Kirk provides evidence-based nutrition support for people living with IBS and other digestive conditions. Consultations focus on understanding your symptoms, improving confidence around food and developing a personalised approach that supports your digestive health and quality of life.

If you're struggling with ongoing digestive symptoms, you don't have to work through them alone.

Book a consultation to receive personalised, evidence-based nutrition support.

References

Maroun P, Bitar L, Al Obaidi S, et al. Association between endometriosis and irritable bowel syndrome: A systematic review and meta-analysis. Frontiers in Medicine. 2022.