What are the Main Symptoms of Endometriosis?-image

 What are the Main Symptoms of Endometriosis?

Medically Reviewed by Hertility on March 28, 2024

Endometriosis is a common reproductive health condition that affects 1 in 10 in the UK. It’s characterised by painful, heavy periods as well as other, often debilitating symptoms. Here we go through each of the main symptoms in detail, so you know what to look out for and when to get checked. 

Quick facts:

  • Intense period pain is usually the most common symptom of endometriosis.
  • Other symptoms can also include heavy periods, pain during or after sex, pain while peeing or pooing, fatigue and fertility struggles.
  • Taking a Hormone & Fertility test can help you investigate any symptoms

Endometriosis in the UK

In the UK, endometriosis affects around 1.5 million women and people assigned female-at-birth (AFAB). That’s 1 in 10 who are currently living with the condition, regardless of race or ethnicity (1).

People with endometriosis often experience very painful periods as well as a host of other symptoms. Many people live with endometriosis for a long time before getting diagnosed. Sometimes up to 7 years or more. 

This is often the result of a general lack of awareness about the condition, dismissal of women’s pain and symptoms having a lot of crossover with other conditions.

So what are the main symptoms of endometriosis? Here’s what to look out for if you suspect you, or someone close to you, may have the condition.

What is endometriosis?

Endometriosis is a chronic reproductive health condition where cells similar to those lining the uterus grow in other parts of the body. Endometrial tissues and lesions are found in the ovaries and Fallopian tubes. 

They can sometimes also grow in the vagina, cervix, vulva, bowel, bladder and rectum. Rarely, do they appear in other parts of the body, like the lungs, brain, and skin (2).

Just like the lining of the uterus, these cells build up and eventually shed. But unlike your period which drains through the vagina, this blood and tissue has nowhere to go. This can cause inflammation, crippling pain and a long list of other symptoms.

Endometriosis can affect women of any age, including teenagers.

What are the main symptoms of endometriosis?

Here are the most common symptoms of endometriosis (3): 

  • Painful periods that stop you from doing your normal activities
  • Heavy periods
  • Chronic pelvic pain
  • Pain during and/or after sex
  • Abdominal bloating or other gastrointestinal issues such as constipation and diarrhoea
  • Chronic pain and fatigue
  • Pain during peeing  or pooping, especially during periods 
  • Mental health struggles
  • Difficulty getting pregnant because of one or more of the above symptoms.

Severe period pain 

Severe period and pelvic pain are often reported to be the most debilitating symptoms of endometriosis. This pain is often described as ‘a razor blade pain’. 

During your menstrual cycle, the lining of your uterus (endometrium) is built up to support a potential pregnancy. If its baby-making dreams are not fulfilled, your body releases chemicals called prostaglandins. 

Prostaglandins cause the uterus to contract and your endometrium sheds. Cue, your period. These contractions are what cause period pain.

With endometriosis, the endometrial-like cells that have grown outside of the uterus also build up and shed. This internal bleeding leads to inflammation, intense pain and a buildup of scar tissue and adhesions (a type of tissue that can bind your organs together). 

Usually, the first or second day of your period is the most painful. But in cases of endometriosis, the crippling pain usually kicks in a few days before your period’s arrival. It can also make an unwelcome return during ovulation or even throughout the month. 

People can also experience chronic pain, increased lower back and pain around their legs which increases around their periods. “Endo belly” is a common term used to refer to the uncomfortable abdominal symptoms associated with endometriosis.

Heavy periods

Another common endometriosis symptom is heavy periods. Heavy periods are defined as:

  • Bleeding for more than 7 days.
  • Having to change your period product every hour or two for several hours in a row.
  • Needing to wear more than one period product at once.
  • Regularly experiencing leaks.
  • Needing to wake up at night to change your period products.
  • Passing blood clots that are bigger than a 10p coin.

If your periods are painful or heavy it’s important to seek medical advice. Monthly heavy bleeding can increase the risk of anaemia (iron deficiency) which can result in symptoms of fatigue, feeling cold often and hair thinning.

Pain during or after sex

Another common symptom of endometriosis is pain during or after vaginal penetration. This can be caused by endometrial lesions growing in the pelvic region and becoming inflamed during or after sex.

This pain is called dyspareunia. It has been reported to feel like a stabbing shooting pain, usually felt deep inside the pelvis.

Any unwanted pain during sex is not normal. If you experience any pain during or after sex or any bleeding, get it checked out. There is also mental health support available if you feel your intimacy is being affected by pain during sex.

Bowel and urination pain

Endometrial lesions can sometimes find their way to the surface of the bowel or even penetrate its wall. This can cause uncomfortable symptoms such as pain when urinating or passing bowel movements or noticing blood in your urine or poo.

Pain during urination can sometimes be misdiagnosed as a UTI. If you’re in pain when passing urine or poo or if you notice any blood in either, get it checked out to understand what might be the cause.

Bloating and gastrointestinal issues

People with endometriosis can also experience bloating and gastrointestinal issues. These symptoms are similar to those of irritable bowel syndrome (IBS). Including diarrhoea, constipation and bloating. These symptoms are often affected by your cycle and can worsen in the days before your period.

Fertility problems

Unfortunately, endometriosis can affect your fertility. Infertility affects about 30-50% of those with endometriosis, but there are no definitive answers (yet) as to why—only theories.  

However, this does not mean that if you have endometriosis you can’t conceive. Even in cases of severe endometriosis, natural conception is possible. 

Mental health impacts

Living with a chronic condition can be tough and often isolating. Endometriosis can affect various aspects of life from personal to professional relationships, which can impact your mental health. 

If you feel like endometriosis is impacting your mental health, there are online support communities like Endometriosis UK. You can also talk to our Fertility Counsellors for any mental health concerns relating to your fertility. 

Getting to the bottom of symptoms

Just like any reproductive health condition, endometriosis varies from person to person. Not everyone with endometriosis will experience all of these symptoms to the same severity. Some people may not experience any of these symptoms at all. 

Having severe pain or very heavy periods is not necessarily a sign of more severe endometriosis. It’s also important to remember that each of these symptoms can also be caused by other conditions. 

If you’re experiencing any of the symptoms listed above, it’s important to seek medical advice to clarify the cause. Our At-home Hormone & Fertility tests can help you take the first steps towards getting to the root of any symptoms and on the road to a diagnosis. 
We can also support you with getting a tailored care plan from one of our Private Gynaecologists.


  1. https://www.endometriosis-uk.org/what-endometriosis
  2. https://www.womenshealth.gov/a-z-topics/endometriosis
  3. https://www.nhs.uk/conditions/endometriosis/
Grace Firmin-Guion BA (Hons)

Grace Firmin-Guion BA (Hons)

Grace is a content marketer with a strong passion for writing and women’s health. She holds a BA Hons in journalism from the University of Kingston and is currently the Marketing and Communications Manager at Hertility Health.

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