What is endometriosis?

Endometriosis is a gynaecological disorder affecting the female reproductive organs, and 11% of women aged 15-44 have the condition.

If you have endometriosis, tissue similar to the lining of your uterus (endometrium) grows in places it shouldn’t, such as on the ovaries, bowel, fallopian tubes, cervix and bladder. In rare cases, it can spread beyond the pelvic region.

This misplaced endometrial tissue undergoes the same hormonal changes as the tissues in the uterus do during the menstrual cycle. This means the tissues grow, thicken, and break down, which can cause inflammation and pain, as there is no way for the broken-down tissues to leave your body.

This trapped tissue can cause scarring, severe period pain, fertility problems, and adhesions (where the misplaced tissues cause pelvic organs to stick together). In some cases, a type of cyst called an endometrioma can form.

What are the symptoms of endometriosis?

Endometriosis has a wide range of symptoms, and diagnosing it can be difficult. Surprisingly, people with mild endometriosis might have the most severe symptoms, while people with a more extreme condition might only experience mild symptoms.

Common signs and symptoms of endometriosis include:

Painful periods (also known as dysmenorrhea)
Cramping similar to period pain, but at any time of the month
Pain during or after intercourse
Pain when using the toilet, and changes to your urine and stool
Excessive bleeding either during your period or between periods
Infertility and difficulty becoming pregnant. Endometriosis is one of three main causes of female infertility, but many people with endometriosis are still able to get pregnant.

What are the causes of endometriosis?

There is no known cause of endometriosis, but a combination of theories could provide some answers as to how endometriosis occurs.

The condition could be linked to genetics, as it tends to run in families, and is more common in some ethnic groups than others. It could also be linked to a problem with the immune system.

It is also believed that endometriosis could be caused by menstrual blood flowing in the wrong direction. This could cause endometrial cells to enter the fallopian tubes and the pelvic cavity, instead of being released from the body as normal (retrograde menstruation).

How is endometriosis diagnosed?

The only method for certain diagnosis of endometriosis is via a laparoscopy. This is a mildly invasive surgical procedure, where a surgeon passes a thin tube through a small cut in your abdomen. This is so that they can view endometrial tissues, and take samples of them for analysis.

However, before having a laparoscopy, an ultrasound scan is recommended. It is less invasive, and can help rule out or confirm other potential causes of your symptoms without needing surgery.

A transvaginal ultrasound is the most common form of ultrasound scan for endometriosis assessment. This involves a small ultrasound probe (a transducer) being inserted into your vagina, to generate images of your reproductive organs. In some cases, an external ultrasound of the abdomen is also effective.

Can you see endometriosis on an ultrasound?

While ultrasound cannot definitively diagnose endometriosis, it can allow doctors to see potential indicators, such as the presence of cysts (possible endometriomas) and misplaced endometrial tissue that has become deeply embedded in another organ. However, it is unlikely they would see small endometrial tissues, which are only on the surface of an organ, from an ultrasound scan.

How does an endometriosis ultrasound work?

During a transvaginal ultrasound, a small ultrasound probe (a transducer) is inserted into your vagina. The transducer emits sound waves, and collects the echoes produced when the waves bounce off your bodily tissues. These echoes are used to generate images of your reproductive organs and general pelvic area. The process may cause some discomfort, but it is quick and painless, usually lasting 15-30 minutes in total.

Depending on where your consultant or doctor thinks the endometrial tissues have grown, you might need to have a transrectal or abdominal (external) ultrasound scan to get the clearest images of your condition.

💡 Find out more about the different types of ultrasounds.

What does endometriosis look like on ultrasound images?

After your ultrasound scan, a radiologist will review your images, and report on their findings. They’ll be looking for potential cysts (endometriomas), abnormal tissue growth (e.g. large clumps of tissue), and other anomalies that could explain your symptoms, even if they are able to rule out endometriosis.

Once the radiologist has written a report, your consultant or GP can use the findings to decide whether you need a laparoscopy to confirm endometriosis, or to recommend treatments for any diagnosis they can confirm with your results.

How is endometriosis treated?

Endometriosis is a chronic condition, and while it cannot be completely cured, there are many treatment options available. It is important to seek a diagnosis for endometriosis as early as possible, in order to help manage your symptoms.

Endometriosis also worsens with age, so if you are hoping to get pregnant, the earlier you can confirm the condition, the sooner you can begin family planning.

Medicinal treatments for endometriosis:

Painkillers, such as ibuprofen and paracetamol, to ease symptoms.
Hormonal contraceptives, including the combined pill, contraceptive patch, or intrauterine system (IUS) to help prevent monthly growth and build-up of endometrial tissue by regulating the menstrual cycle.
Danazol, which is a medication to stop menstruation and reduce symptoms. It can have side effects, including acne and excessive hair growth on the face and body.

Surgical treatment options for endometriosis:

Surgical removal of endometrial growths can be carried out without damaging the reproductive organs. This is for people who want to get pregnant or do not experience relief from hormone treatments.
A total hysterectomy (surgery to remove the uterus, cervix and ovaries) is offered as a last resort if no other treatments are successful. Having a hysterectomy means you won't be able to have children, and while it is an option, it is not commonly offered as an endometriosis treatment.

💡 Next steps:

- Book a private ultrasound scan to assess endometriosis symptoms, with a quick referral and fast results from our clinical team
- Visit our news page to learn more about ultrasound scans