Bowel Endometriosis: Symptoms, Diagnosis and Treatment Options

If bowel symptoms flare around your period, being told it’s ‘just IBS’ can leave you with more questions than answers. Although irritable bowel syndrome (IBS) is a real condition that deserves care, it may not always explain everything that’s happening with your bowel. 

Bowel endometriosis is when tissue similar to your womb lining grows on or into the bowel, and is one reason your symptoms may become more noticeable around the time of your period. It is a recognised, treatable condition, so you are not imagining it. Your symptoms deserve further investigation. 

Here, we explain what bowel endometriosis is, what to look out for, how it is diagnosed and what treatments are available. This article is for information purposes only, though, and does not provide a diagnosis or replace personalised medical advice.

What is Bowel Endometriosis? 

Endometriosis develops when tissue similar to the womb lining grows elsewhere in the body. These areas can contribute to inflammation, pain and scarring. With bowel endometriosis, this tissue affects the bowel surface or grows into the bowel wall.

Bowel endometriosis most commonly affects the lower bowel, particularly the rectum, sigmoid colon, and the point where they join, called the rectosigmoid. Less commonly, endometriosis can affect the small intestine or appendix.

Endometriosis affects 1 in 10 women of reproductive age.* Deep bowel endometriosis occurs in between 5 and 12% of people diagnosed with endometriosis.⁺ However, some studies suggest that the prevalence of bowel endometriosis could be up to 37%.ⱽ

Is bowel endometriosis the same as endometriosis of the bowel wall?

Although bowel endometriosis and endometriosis of the bowel wall often overlap, they are not always used identically. Bowel endometriosis also covers the growth of womb-like tissue on the outside of the bowel or extending into the bowel wall.   

Disease growing beneath the surface is called deep endometriosis, sometimes described as deep infiltrating endometriosis. It may form nodules or lumps containing endometriosis tissue and scarring, while superficial disease stays closer to the surface.

Bowel symptoms do not automatically mean endometriosis has entered the bowel wall. Endometriosis elsewhere in the pelvis, adhesions and coexisting gut conditions can also contribute to symptoms.

What causes bowel endometriosis?

The exact cause of bowel endometriosis is not fully understood, but there are several theories that have been proposed for the potential causes. One theory involves retrograde menstruation, when menstrual blood flows backwards through the fallopian tube into the pelvis. However, this does not explain why everyone develops endometriosis, . Other factors that may influence the development of bowel endometriosis include:

• Genetics – some evidence suggests that bowel endometriosis can run in families*

• Immune system changes – systemic and local immune dysfunction can stop your body from clearing the tissue that causes bowel endometriosis from the body⁺

• Hormonal factors – increased oestrogen production can make your symptoms worseⱽ

What Are the Symptoms of Bowel Endometriosis?

Bowel endometriosis symptoms are usually at their most intense before or during your period, but they do not have to follow a neat monthly pattern. Some people have symptoms between periods, while others have few or no bowel symptoms at all. 

Common bowel symptoms

Some of the possible bowel endometriosis symptoms include: 

• Painful bowel movements, especially around your period and known medically as dyschezia

• Constipation, diarrhoea or alternating between them

• Bloating, sometimes called “endo belly”, that comes and goes

• Cramping or pain in your lower abdomen or rectum

• Feeling that you have not fully emptied your bowels

• Repeated urges to poo, even when little comes out, known as tenesmus-type sensations

• Rectal bleeding or blood in your poo during a period, although this is less common, and should always be checked

Other symptoms that may point to endometriosis

Alongside specific bowel endometriosis symptoms, there are also several endometriosis-specific symptoms to look out for, including:

• Period pain that interferes with work, sleep or everyday activities or lingers after your period has finished

• Heavy periods

• Pain or bleeding during or after sex, particularly deep pain

• Ongoing pelvic pain

• Fatigue

• Difficulty getting pregnant

Bowel endometriosis vs IBS: how to tell the difference

Bowel endometriosis and IBS are separate conditions that share similar symptoms, including abdominal pain, bloating, constipation and diarrhoea, and it is possible to have endometriosis and IBS at the same time, making distinguishing between the 2 conditions challenging. 

IBS affects 5 to 10% of the general population, while 1 in 10 women are affected by endometriosis.* If you are getting painful periods, painful sex or severe pain when going to the toilet, it is important to speak to a clinician for a diagnosis who can investigate both gynaecological and digestive causes. You should avoid trying to self-diagnose based on your symptoms as this could lead to misdiagnosis or incorrect treatment. 

When to see a GP

Suspected bowel endometriosis, or cyclical bowel symptoms that occur around your period and disrupt your daily life, warrant further investigation with a clinician, even if you are already receiving treatment. Let the clinician know if you already have an endometriosis or IBS diagnosis and if you are experiencing any new or worsening bowel symptoms. It can help to keep a symptom diary to help you start a conversation with a doctor, which includes:

• Your symptoms

• When the symptoms occurred, for how long for and the severity

• When you had your period

If you notice any blood in your poo, a persistent change in bowel habit, unexplained weight loss or symptoms that are new or worsening, make an urgent appointment with your GP. Do not wait for another period to see whether bleeding repeats.

You should:

• Ask for an urgent GP appointment or contact NHS 111 for black or dark-red poo, bloody diarrhoea or abdominal pain that is getting worse

• Go to A&E for sudden or severe abdominal pain, especially with vomiting, swelling or inability to pass poo or wind

• Go to A&E or call 999 for continuous or heavy rectal bleeding, such as large clots or toilet water turning red. Call 999 if you collapse or cannot travel safely

How is Bowel Endometriosis Diagnosed?

Diagnosing bowel endometriosis usually involves several steps, including discussing your symptoms with a clinician, examination and imaging, and referral to a specialist endometriosis service so you can receive the right treatment. In the UK, it takes, on average, 9 years and 4 months to receive an endometriosis diagnosis,* so speaking to your doctor as soon as you notice symptoms can help you get the help you need faster. 

Your first appointment and referral

At your first appointment, your GP will ask about your periods, bowel symptoms, pain, family history and pregnancy plans. They may offer an abdominal or internal pelvic examination, with your consent. You can ask for a chaperone, decline an internal examination, or ask them to stop.

Anyone who is suspected of having endometriosis in the UK should be offered a transvaginal ultrasound, even if their pelvic or abdominal examination is normal. If bowel endometriosis is suspected or confirmed, the National Institute for Health and Care Excellence (NICE) recommends a referral to a specialist endometriosis service. These services have access to professionals experienced in complex disease, including colorectal surgeons.**

Treatment for Bowel Endometriosis

There’s no need to suffer with bowel endometriosis symptoms alone; there are treatments available that can help make your daily life more manageable. Although there is no cure and treatment depends on your symptoms, the location and extent of disease, any bowel narrowing, and your fertility plans, treatments can improve your symptoms and quality of life.   

If you’re worried about surgery, not every case of bowel endometriosis requires it. Some people manage symptoms medically, while others can monitor them if symptoms are mild. Even lifestyle changes can help to bring about small improvements in the way you feel on a daily basis.

Let’s take a closer look at some of the treatments available for bowel endometriosis. 

Pain relief and symptom management

Several pain relief options are available for bowel endometriosis. These include paracetamol or an anti-inflammatory medicine such as ibuprofen. However, you should speak to a pharmacist or GP, especially if you have stomach, kidney or other medical issues or take other medicines. 

Other pain relief options include:

• A wrapped heat pack or warm compress applied to the affected area

• A TENS machine, if it suits you, which sends low-voltage electrical impulses through sticky electrode pads attached to your skin, interrupting pain signals before they reach your brain

• Activity pacing, which means regulating your exercise and daily physical activities to avoid pain flare-ups, and gradually increasing what you can do

• Pelvic floor physiotherapy, which can help ease tense muscles that may be adding to bowel endometriosis or pelvic pain

• A referral to a specialist pain service, which you can ask your clinician about

Hormonal treatments

Hormonal treatment aims to reduce the activity driving endometriosis symptoms. Options include:

• Combined hormonal contraception, such as the combined pill

• Progestogens, including tablets and some contraceptive methods

• A hormonal intrauterine system, or IUS

• GnRH agonists, sometimes called GnRH analogues

• Certain GnRH antagonist medicines, depending on suitability and prescribing guidance

These treatments can reduce pain and bleeding by suppressing or reducing your usual menstrual cycle activity, but they do not surgically remove lesions or reliably reverse established scarring and bowel narrowing. They may not suit everyone, especially if you plan to get pregnant soon, and it’s also worth noting that not every hormone treatment provides contraception. You should discuss potential side effects, contraindications and pregnancy plans before choosing treatment with a clinician. 

Surgery for bowel endometriosis

Surgery for bowel endometriosis is a big step and is usually considered if your symptoms are severe, including a narrowed bowel, or if your current medical treatments have not worked. Discuss it with your clinician or surgeon so you fully understand the benefits, risks, and other considerations, such as recovery time.

There are several potential surgical options available for bowel endometriosis. They are:

The right surgical procedure for you depends on the size, depth, and location of the disease. Risks include bleeding, infection, injury to nearby organs, leakage from the bowel and an abnormal connection called a fistula. Bowel habits may change afterwards, including urgency, frequent poos or difficulty emptying.

A temporary stoma, where poo passes through an opening in the abdomen into a bag, is sometimes needed. Most people do not need one, but the likelihood varies with the operation.

Recovery usually takes weeks, and bowel function may take longer to settle. Your surgeon can discuss how much time off work you will need, which foods to eat and avoid, activities you can do during recovery, and any symptoms that require urgent help.

Care should involve an experienced multidisciplinary team, including a specialist gynaecologist and, where appropriate, a colorectal surgeon. Surgery can help, but symptoms or disease may return. 

Diet, lifestyle and gut health

No diet has been proven to remove bowel endometriosis, but making some changes to your diet and lifestyle may help manage bowel symptoms, particularly alongside IBS.

Some of the things you can do include:

• Eating regularly and keeping a brief food-and-symptom diary

• Eating an anti-inflammatory diet – rich in vegetables, fruit, wholegrains and oily fish, and lower in ultra-processed food

• Taking probiotics to support your gut health*

• Drinking enough fluid, especially if constipation is a problem

• Adjusting fibre gradually rather than suddenly adding large amounts

• Trying gentle movement and protecting time for sleep

• Getting support with stress when it worsens symptoms

If you have known or suspected bowel narrowing, speak to your clinician before increasing fibre or using laxatives. A dietitian may suggest a short low-FODMAP trial for IBS-type symptoms, followed by food reintroduction. It is not a treatment for endometriosis or a lifelong list of forbidden foods. There is also no established evidence that “gut healing” supplements cure bowel endometriosis.

Living With Bowel Endometriosis

Bowel endometriosis can take its toll emotionally and practically, especially if unpredictable pain and bowel urgency affect your work, relationships, sex life or daily life. Factors like fatigue can also make even a quiet day more challenging to navigate, and bowel endometriosis can also affect wider aspects of your health and life, including fertility and mental health.

Bowel endometriosis and fertility

Endometriosis can affect fertility, but it does not mean you’ll never be able to get pregnant. Many people conceive naturally, while some may need a little extra help from fertility treatment. 

If you are trying to get pregnant, speak to your GP or a fertility specialist as early as possible. If endometriosis has been confirmed, you do not need to wait a year before asking for help with fertility. Surgery plans may also need to be adjusted if you want to get pregnant.

Looking after your mental health

Repeatedly having to explain pain, or being dismissed, can leave you anxious, angry or exhausted. Support for that emotional impact belongs alongside physical treatment.

If you're struggling, speak to your GP about counselling or talking therapies. Getting psychological support does not mean your symptoms are psychological.

Endometriosis UK offers a helpline, local and online support groups, and other support resources. Its helpline is 0808 808 2227, but check their website for current opening times. 

How to advocate for yourself

Whether you’re preparing for your first GP consultation or a follow-up because you’ve noticed new symptoms or don’t feel your condition is being well managed, you can do several things to support or prompt the discussion, including keeping a symptoms diary. You can also make a list of questions that you may want to ask, such as:

• Could endometriosis explain this pattern?

• Do I need assessment for other bowel conditions as well?

• Is referral to a specialist endometriosis service appropriate?

• What happens if the scan is normal?

• When will we review the plan?

If your concerns remain unanswered, ask for another appointment or a second opinion. You can also ask for your symptoms and the agreed next steps to be recorded for your records.

FAQs

Can endometriosis cause bowel problems?

Yes. Endometriosis can affect the bowel directly, causing painful bowel movements, constipation, diarrhoea or bloating. Pelvic endometriosis can also contribute to bowel symptoms without growing into the bowel wall. IBS and other bowel conditions may coexist, so symptoms alone cannot show where endometriosis is present.

What does bowel endometriosis pain feel like?

It depends. Bowel endometriosis pain can differ from person to person. It may feel like sharp or stabbing rectal pain, lower-abdominal cramping, a deep ache or pressure when you poo. Some people notice pain before, during or after a bowel movement. Symptoms often worsen around a period, but there is no single pain pattern that confirms the diagnosis.

Can bowel endometriosis go away on its own?

No. Bowel endometriosis doesn't usually disappear completely without treatment. Symptoms can fluctuate and may ease with hormonal treatment or after menopause, but scarring or narrowing can remain.

Does bowel endometriosis show up on an ultrasound?

Yes. It can, particularly on a specialist transvaginal ultrasound performed by someone experienced in detecting deep endometriosis. MRI may also help map bowel involvement. However, a normal ultrasound does not rule out endometriosis. If symptoms continue, ask your doctor what further assessment or referral is needed.

Can bowel endometriosis cause blood in your poo?

Yes. However, rectal bleeding is less common than pain, bloating or altered bowel habits. It may happen around your period. Blood in your poo still needs checking, because piles, fissures, inflammatory bowel disease (IBD) and other conditions can cause bleeding. Heavy bleeding or black poo needs urgent medical attention.

Can you have endometriosis and IBS at the same time?

Yes. One does not rule out the other, and both can contribute to pain, bloating and bowel changes. Treating IBS may help some symptoms while endometriosis needs separate care. If an existing IBS diagnosis doesn't adequately explain your symptoms, discuss further assessment with your GP.