Endometriosis: Symptoms, Diagnosis and What You Need to Know

Endometriosis symptoms can look very different from one woman to another. For some, the first sign is periods that have always been unusually painful. For others, it may be pelvic pain, pain during sex, bowel or bladder symptoms, difficulty becoming pregnant, or simply a feeling that something isn’t right.

In this post, I’ll talk you through what endometriosis is, the symptoms that can sometimes point towards it, what to discuss with your healthcare provider if you’re concerned you may have endometriosis, and what the next steps might look like.

Endometriosis is common – affecting around 1 in 10 women – but getting a diagnosis is not always straightforward. In fact, according to the latest figures from Endometriosis UK, it now takes an average of 9 years and 4 months from first seeking medical help to receiving a diagnosis in the UK. Symptoms can overlap with other conditions which makes diagnosis difficult and, importantly, endometriosis doesn’t always show up on an ultrasound or MRI scan.

This is something I think is particularly important for women to understand. If your periods or pelvic symptoms are having a significant impact on your life, being told that your scan is “normal” doesn’t necessarily mean that nothing is wrong.

So, what actually is endometriosis, what symptoms should make us think about it, and how is it diagnosed?

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What is endometriosis?

Endometriosis is a condition where tissue similar to the lining of the womb is found elsewhere in the body.

It is most commonly found within the pelvis – around the womb, ovaries and fallopian tubes – but it can also involve the bowel, bladder, ureters and other areas. When it affects an ovary it can form a cyst called an endometrioma, sometimes known as a “chocolate cyst”.

Endometriosis can cause inflammation and scarring wherever it is found. In some women, this can lead to adhesions, where structures within the pelvis become stuck together rather than moving freely which can cause constant pain.

One of the slightly confusing things about endometriosis is that the amount of disease doesn’t necessarily tell us how much pain somebody will experience. A woman with relatively limited endometriosis can have significant symptoms, while another with more extensive disease may have surprisingly little pain.

That is why the symptoms – and their effect on your life – matter so much.

What causes endometriosis?

The short answer is: we don’t completely know.

There are several theories about why endometriosis develops, and it is likely that a combination of genetic, hormonal, immune and cellular factors is involved.

We do know that there appears to be a family connection. Having a first-degree relative, such as a mother or sister, with endometriosis increases the likelihood of having it yourself, which is why NICE now specifically recommends asking about family history when assessing possible endometriosis.

What are the symptoms of endometriosis?

This is where endometriosis can become difficult to recognise, because there isn’t one single set of symptoms that everybody experiences.

Some of the more common endometriosis symptoms include:

• very painful periods
• pelvic pain, either during periods or at other times
• deep pain during or after sex
• pain when opening your bowels, particularly around your period
• bloating, constipation or diarrhoea that seems to worsen around menstruation
• pain when passing urine, particularly around your period
• blood in the urine or bleeding from the bowel associated with menstruation
• fatigue
• difficulty becoming pregnant.

One of the most useful clues is often the pattern.

If symptoms reliably appear or become worse just before or during your period, tell your doctor. It can be surprisingly helpful in piecing everything together.

What does endometriosis pain feel like?

There isn’t one particular type of pain that means somebody has endometriosis.

Some women describe intense cramping during their periods. Others experience a deep aching or dragging sensation in the pelvis. There may be sharp pain with bowel movements, pain during sex, back pain or discomfort that starts several days before a period and continues afterwards.

And this raises another question I hear frequently: how painful is a normal period supposed to be?

Some cramping and discomfort during menstruation is common. But pain that regularly stops you doing normal things deserves attention.

If your periods mean missing school or work, cancelling plans, being unable to exercise, spending hours in bed, vomiting or fainting with pain, or regularly needing significant pain relief just to function, I wouldn’t simply dismiss that as “normal period pain”.

And the fact that your periods have always been like this doesn’t necessarily make them normal.

This is particularly important for teenagers and younger women, where severe period pain can sometimes be normalised for years before endometriosis is considered.

If the symptoms around your cycle are predominantly emotional rather than painful, there are other hormonal conditions worth considering too. I’ve written separately about PMDD symptoms and how cyclical hormone sensitivity can affect both physical and emotional wellbeing.

Can endometriosis cause bowel symptoms?

Yes – and this is an area that can understandably cause confusion.

Endometriosis can involve the bowel itself, but women can also experience bowel symptoms without endometriosis actually growing into the bowel.

Symptoms may include bloating, constipation, diarrhoea, painful bowel movements, rectal or pelvic pain and, less commonly, bleeding from the rectum associated with menstruation.

The difficulty is that these symptoms can look very similar to irritable bowel syndrome (IBS).

Bloating and changes in bowel habit are extremely common and there are many possible causes. I’ve written previously about the wider relationship between oestrogen and gut symptoms.

But with possible endometriosis, I am particularly interested in timing. If bowel pain or bloating consistently becomes much worse around your period, that cyclical pattern is worth mentioning.

Can endometriosis affect the bladder?

It can.

Some women experience bladder discomfort or pain when passing urine that becomes noticeably worse around their periods. More rarely, there may be blood in the urine associated with menstruation.

Deep endometriosis can also involve the bladder or ureters – the tubes carrying urine from the kidneys to the bladder.

This is important because suspected deep endometriosis involving the bowel, bladder or ureters should be assessed by a specialist endometriosis service.

Can endometriosis cause pain during sex?

Yes. Deep pain during or after penetrative sex is one of the recognised symptoms of endometriosis.

There are, of course, lots of possible reasons for painful sex, and having this symptom doesn’t automatically mean you have endometriosis.

But it is something worth mentioning during a consultation. You shouldn’t feel embarrassed about bringing it up, and it certainly isn’t something you should simply feel expected to tolerate.

Can endometriosis affect fertility?

It can – but having endometriosis certainly does not mean that you won’t be able to become pregnant.

Many women with endometriosis conceive naturally.

For others, endometriosis may make conception more difficult. Inflammation, ovarian endometriomas, adhesions and disease affecting the relationship between the ovaries and fallopian tubes can all potentially contribute.

If you are having difficulty becoming pregnant and have symptoms suggestive of endometriosis, it is particularly important to mention both because your fertility plans can influence which investigations and treatments are most appropriate. NICE specifically includes infertility alongside characteristic symptoms as a reason to suspect endometriosis.

How is endometriosis diagnosed?

There isn’t one single investigation that gives us every answer.

For me, diagnosis starts with something much more basic: listening properly to the story.

I want to understand when the symptoms began, what your periods are like, where and when you experience pain, whether sex is painful, whether there are bowel or bladder symptoms, and – importantly – whether any of these symptoms change at different points in your menstrual cycle.

I’d also want to know how much they are affecting you.

Are you missing work? Avoiding exercise? Planning your life around your periods? Is sex becoming difficult? Are you frightened about being away from home when your period starts?

These details matter.

Keeping a period and symptom diary for a couple of months can be incredibly useful. NICE specifically recommends this because it can make patterns much easier to recognise during a consultation.

Depending on your symptoms, an abdominal and pelvic examination may also be appropriate.

Can an ultrasound detect endometriosis?

Ultrasound is an important part of the investigation. Current NICE guidance recommends offering a transvaginal ultrasound scan to everyone with suspected endometriosis, even if the abdominal or pelvic examination is normal. If an internal scan isn’t appropriate (younger or virgin women) or isn’t something you want, a transabdominal pelvic ultrasound can be considered instead.

Ultrasound can be particularly useful for identifying ovarian endometriomas and some forms of deep endometriosis. It can also identify other possible explanations for symptoms, such as fibroids or ovarian cysts.

But there is an important limitation: Ultrasound may not always pick up on subtle signs.

Can I have endometriosis if my ultrasound is normal?

Yes. This is probably one of the most important messages in this entire article. A normal ultrasound does not rule out endometriosis.

Some types of endometriosis, particularly superficial disease, can be difficult to see on routine imaging. The expertise of the person performing and interpreting the scan can also make a difference when looking for deep endometriosis. NICE explicitly advises clinicians not to exclude endometriosis because examination and ultrasound findings are normal.

So if your scan has been reported as normal but your symptoms still strongly suggest endometriosis, that shouldn’t necessarily be the end of the conversation.

Can an MRI detect endometriosis?

MRI can be particularly useful when deep endometriosis is suspected and we need more information about where the disease may be. For example, it can help assess possible involvement of the bowel, bladder and other pelvic structures. NICE recommends that specialist ultrasound and pelvic MRI used for deep endometriosis are planned and interpreted by somebody with expertise in gynaecological imaging.

But MRI isn’t perfect either. A normal MRI does not completely rule out endometriosis.

Do I need a laparoscopy to diagnose endometriosis?

Not necessarily.

A laparoscopy is keyhole surgery performed under a general anaesthetic. A camera is passed into the abdomen so that a surgeon can look directly at the pelvis and, where appropriate and agreed beforehand, any endometriosis found may sometimes be treated during the same operation. Laparoscopy remains an important part of diagnosis and treatment, but not every woman with suspected endometriosis needs surgery simply to establish what might be causing her symptoms.

NICE advises that laparoscopy can still be considered when endometriosis is strongly suspected even when ultrasound or MRI scans have been normal. The decision needs to take into account your symptoms, previous investigations, fertility plans, response to treatment and, importantly, what you want.

Is there a blood test for endometriosis?

At present, there isn’t a routine blood test that can reliably diagnose or rule out endometriosis. You may have heard of a blood marker called CA125, but it isn’t accurate enough for this purpose and NICE specifically advises against using CA125 to diagnose endometriosis.

However, this is an area where things are beginning to change.

What about the new saliva test for endometriosis?

This is one of the more interesting recent developments. A test called Ziwig Endotest® analyses tiny molecules called microRNAs within a saliva sample, looking for a particular biological signature associated with endometriosis.

I’ve written a separate blog post explaining how the new saliva test for endometriosis works, how accurate Endotest appears to be and where it may fit into the diagnostic pathway.

The research so far is certainly encouraging, although it is still a relatively new test and it shouldn’t be looked at in isolation. I see it as another potential piece of the puzzle. It doesn’t tell us where endometriosis is or how extensive it may be, so imaging and specialist assessment remain important when these are needed.

Why can endometriosis take so long to diagnose?

There are probably lots of reasons. Endometriosis symptoms overlap with other common conditions. Period pain can become normalised. Bowel symptoms may initially look like IBS. Scans may be normal. And different women can experience the condition in completely different ways. Plus women are amazing and ‘just getting on with it’ and getting used to the symptoms as part of their normal life.

If you’ve experienced painful periods since your teens, you may simply assume that this is what periods are like. You might arrange work, holidays, exercise or social plans around them without really considering how much of your life is being dictated by your menstrual cycle.

That’s why questions such as “How is this affecting your life?” can sometimes tell us more than a pain score.

How is endometriosis treated?

There is no single treatment that is right for everyone with endometriosis. What works best will depend on your symptoms, your priorities and whether fertility is a consideration. Treatment may include pain relief, hormonal treatments, surgery and other ways of managing pelvic pain.

I’ll look at all of these options – including medical and non-medical approaches – in a separate article.

When should I speak to a doctor about endometriosis symptoms?

You don’t need to wait until your symptoms become unbearable, and I’d encourage you to seek medical advice if period pain or pelvic symptoms are regularly interfering with your normal life, if you have persistent pelvic pain, deep pain during sex, bowel or bladder symptoms that seem linked to your menstrual cycle, or difficulty becoming pregnant alongside other possible endometriosis symptoms.

And if you’ve already sought help but still feel that something hasn’t been explained, it is reasonable to go back.

A “normal” scan doesn’t make your symptoms any less real.

The important message

Endometriosis is common, but living with significant pain shouldn’t simply be accepted as part of being a woman.

There isn’t always one symptom, scan or test that gives us the answer. Often, diagnosis comes from putting several pieces of the puzzle together – your symptoms, their relationship to your menstrual cycle, examination, imaging and, when appropriate, further investigations.

Perhaps most importantly, it begins with listening to the patient.

If your periods or pelvic symptoms are changing the way you live your life, that’s worth talking about. And if your ultrasound has been normal but the symptoms still fit, endometriosis should not automatically be dismissed.

Our diagnostic options are improving, including promising developments such as the new saliva test for endometriosis, but no new technology replaces a thoughtful clinical assessment.

Sometimes the most important first step is simply recognising that what you’ve been putting up with for years deserves a proper explanation.

Reliable further information

For anyone who wants to read further, I’d point patients towards NICE’s endometriosis diagnosis and management guidance and the Royal College of Obstetricians and Gynaecologists’ endometriosis patient information. Both are good UK sources and, importantly, reinforce the message that normal imaging does not necessarily exclude endometriosis.

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This article is intended for general information and education. It cannot replace an individual medical assessment, diagnosis or treatment.