Endometriosis and IBS: Unraveling the Connection

I have struggled with gastrointestinal symptoms for the past few years. 

It has led me to think outside the box for my "why." Not only have I been diagnosed with irritable bowel syndrome (IBS), but I have had doctors tell me my symptoms may also be attributed to endometriosis. 

Having these two diagnoses mentioned to me has made me question if these two could be related. To my surprise, it seems that many people living with endometriosis have been told they have IBS before an endometriosis diagnosis.

Endometriosis is when cells resembling the lining of the uterus (endometrial gland and stroma-like tissue) grow outside the uterus. Endometriosis affects up to 10% of women globally; of those individuals with endometriosis, about 20% suffer from infertility. Symptoms vary and can be explained as chronic pelvic pain, painful menstruation, ovulation pain, or sharp, burning, menstrual-like cramps. 

Many symptoms of endometriosis overlap with those experienced in gastrointestinal (GI) conditions; therefore, the process of reaching a diagnosis is typically delayed between 6 and 11 years. Similar symptoms between both conditions include bloating, cramping, nausea, visceral pain, painful gas, and constipation/diarrhea.

Is it a misdiagnosis, or are GI conditions a genuine co-morbidity? 

This is the question that many studies are trying to determine. Unfortunately, a definitive diagnosis of endometriosis can only be made at surgery, generally via laparoscopy.

A 2008 national case-control study found a significant association between endometriosis and a history of IBS and that individuals with endometriosis are 3.5 times more likely to have received a diagnosis of IBS than those without endometriosis. Furthermore, a 2022 systemic review and meta-analysis concluded that patients diagnosed with endometriosis have roughly a threefold increased risk of developing irritable bowel syndrome compared to individuals without endometriosis.

Why might someone with endometriosis have a delayed diagnosis or be told they have IBS first?  

Well, the majority of sites for endometriosis deposits are areas of the posterior pelvic compartment peritoneum near the terminal large bowel. The inflammatory nature of the lesions and local prostaglandin release may explain any altered bowel function. Typically, many practitioners do not automatically assume altered bowel function may be caused by endometriosis; their first assumption would be to refer to a GI doctor to rule out GI causes.

Can dietary changes help with symptom management? 

Visceral hypersensitivity, a hallmark of IBS, is also found in individuals with endometriosis, suggesting the Low FODMAP diet may be an attractive therapy in this group. This diet is a diagnostic tool used to help identify dietary triggers and includes three phases: an elimination phase, a challenge/reintroduction phase, and a maintenance phase. 

The role of diet is likely just as important for symptom control in endometriosis as in IBS. A 2017 study in the Australian & New Zealand Journal of Obstetrics & Gynecology showed that the Low FODMAP diet was beneficial in a significantly higher percentage of patients with endometriosis than in those with whom such a diagnosis had not been made. A known diagnosis of endometriosis conferred a threefold greater chance of responding to the diet.

You can find a dietitian trained in the Low FODMAP diet for IBS to help you navigate the different phases of the Low FODMAP diet in the FODMAP Dietitians Directory through Monash University. As always, if you are experiencing endometriosis and IBS symptoms, it is essential to speak with your healthcare provider to evaluate them appropriately.

1. _{World Health Organization. (2023). Endometriosis. World Health Organization.} 
2. _{Ballard, K. D., Seaman, H. E., de Vries, C. S., & Wright, J. T. (2008). Can symptomatology help in the diagnosis of endometriosis? Findings from a national case-control study--Part 1. BJOG : an international journal of obstetrics and gynaecology, 115(11), 1382–1391.}  
3. _{Seaman, H. E., Ballard, K. D., Wright, J. T., & de Vries, C. S. (2008). Endometriosis and its coexistence with irritable bowel syndrome and pelvic inflammatory disease: findings from a national case-control study--Part 2. BJOG : an international journal of obstetrics and gynaecology, 115(11), 1392–1396.}  
4. _{Nabi, M. Y., Nauhria, S., Reel, M., Londono, S., Vasireddi, A., Elmiry, M., & Ramdass, P. V. A. K. (2022). Endometriosis and irritable bowel syndrome: A systematic review and meta-analyses. Frontiers in medicine, 9, 914356.}
5. _{Moore, J. S., Gibson, P. R., Perry, R. E., & Burgell, R. E. (2017). Endometriosis in patients with irritable bowel syndrome: Specific symptomatic and demographic profile, and response to the low FODMAP diet. The Australian & New Zealand journal of obstetrics & gynaecology, 57(2), 201–205.}