Endometriosis diagnosis: how it works and how long it takes

Short answer: There is no single test for endometriosis. A GP asks about your symptoms and usually examines you, and the first scan is normally a transvaginal ultrasound. A gynaecologist may follow up with an MRI or a laparoscopy (keyhole surgery). A normal scan does not rule endometriosis out. In the UK it takes 8 years and 10 months on average from first symptoms to diagnosis, and a clear record of your symptoms helps shorten that.

How is endometriosis diagnosed?

Endometriosis is tissue similar to the lining of the womb growing outside the womb, for example on the ovaries or the lining of the pelvis. The WHO estimates it affects about 10% of women of reproductive age, around 190 million worldwide. Symptoms vary widely from person to person, which is what makes diagnosis hard. The usual route looks like this:

1. A conversation with your GP. About period pain, pain during or after sex, pain when you pee or poo around your period, pelvic pain between periods and difficulty getting pregnant.
2. A physical examination. Your doctor checks your abdomen and often does an internal (pelvic) exam.
3. A transvaginal ultrasound. This is the first scan. Since NICE updated its guideline in 2024, GPs in England are told to offer this scan to everyone with suspected endometriosis, even if the examination was normal.
4. Referral to a gynaecologist. If symptoms continue, the scan shows something, or you want to get pregnant.
5. MRI or laparoscopy. Only when needed to confirm the diagnosis or plan treatment.

Not sure your symptoms fit? Start with how to recognise endometriosis symptoms.

Can endometriosis be seen on an ultrasound?

Sometimes. An endometriosis cyst on an ovary (an endometrioma, sometimes called a chocolate cyst) usually shows up well on a transvaginal scan. A specialist scan can also pick up deep endometriosis near the bowel or bladder. Small patches on the lining of the pelvis and adhesions often do not show. That is why NICE is explicit: a normal ultrasound does not exclude endometriosis, and you may still need a referral.

Do you need a laparoscopy to diagnose endometriosis?

Not always anymore. Laparoscopy used to be seen as the only certain way. The European ESHRE guideline from 2022 puts imaging (ultrasound and MRI) first, and keeps laparoscopy mainly for when scans are normal but symptoms continue, or when hormonal treatment does not work or does not suit you. During a laparoscopy the surgeon looks inside through a few small cuts in your belly, and can take a tissue sample or remove patches at the same time.

Worth knowing: treatment for pain, such as painkillers or hormonal medicine, can often start before a diagnosis is confirmed by surgery. Talk to your doctor about what fits your situation.

What about MRI and blood tests?

MRI is not a first test. NICE recommends it mainly to see how far deep endometriosis reaches into the bowel, bladder or ureter, so surgery can be planned. There is no blood test that diagnoses endometriosis, and NICE advises against using the CA125 blood marker to make the diagnosis.

Why does endometriosis take so long to diagnose?

Endometriosis UK found an average of 8 years and 10 months in England and Scotland in its 2024 report, longer than in 2020, and 47% of respondents saw their GP ten times or more before diagnosis. In the Netherlands the average is estimated at around seven years. The main reasons:

• period pain is often treated as normal, by women themselves and by healthcare staff
• symptoms overlap with other conditions, such as irritable bowel syndrome or a bladder infection
• a normal scan is sometimes read as proof that nothing is wrong
• the pill can mask symptoms, so they only show after stopping

How can you get diagnosed faster?

You cannot diagnose yourself, but you can make it much easier for your doctor. What helps:

• Track your symptoms for a few cycles. Note your pain each day (for example on a scale of 0 to 10), when in your cycle it comes, and whether you have pain with sex, peeing or pooing.
• Note what you have tried. Which painkillers, how many, and whether they helped. Whether you miss work or school because of the pain.
• Say the word. Ask directly: could this be endometriosis, and can I have a transvaginal ultrasound?
• Ask for a referral if symptoms continue despite treatment, or if you are trying to get pregnant without success.

In PERIOD. you log your pain and symptoms day by day next to your cycle, so you can show your GP months of data instead of a feeling. The app logs and shows, your doctor makes the diagnosis. For relief in the meantime, see how to ease period cramps. If you are trying for a baby, read our guide to trying to conceive.

Sources: NICE, Endometriosis: diagnosis and management (NG73, updated November 2024); ESHRE, Guideline Endometriosis (2022); WHO, Endometriosis fact sheet (2025); Endometriosis UK, Dismissed, ignored and belittled (March 2024); WOMEN Inc., cost benefit analysis of women's health conditions (2024). This article is general information, not medical advice.

Frequently asked questions

Can a GP diagnose endometriosis?

A GP can suspect it from your symptoms and examination and arrange an ultrasound. A confirmed diagnosis usually comes from a gynaecologist, using ultrasound, MRI or laparoscopy.

Does a normal ultrasound rule out endometriosis?

No. Small patches on the lining of the pelvis often do not show on a scan. If your symptoms continue, a referral to a gynaecologist may still be needed.

Is there a blood test for endometriosis?

No. No blood test can diagnose endometriosis, and NICE advises against using the CA125 marker for it.

How long does it take to get an endometriosis diagnosis?

In the UK almost nine years on average from first symptoms, in the Netherlands around seven. A clear symptom record and asking your doctor about endometriosis by name can help.

Can you get treatment without a diagnosis?

Often, yes. Painkillers and hormonal treatment can start when endometriosis is suspected. You do not always need surgery before you get help.

Want your pain and symptoms per cycle in one overview? Download PERIOD. on the App Store or Google Play.