Endometriosis: Types, causes, symptoms, diagnosis, and treatment

Some disease conditions are thought to be rare, but they are more common than we think. Endometriosis is one of them. Let’s take a deep dive into all about endometriosis. 

A woman lying on a bed with white sheets clutching her tummy

Key takeaways

  • Endometriosis is a condition where tissues similar to the inner lining of the uterus (endometrium) are seen outside of the inner part of the uterus.
  • The exact cause of this condition is unknown, but some factors have been proposed to be contributing to its development, such as genetics and changes in cells.
  • There’s currently no cure for endometriosis. But some treatments can help ease the symptoms. 

Endometriosis is an estrogen-dependent disease. This means that the female hormone, estrogen, facilitates its growth. The condition is seen mostly in females in their reproductive years and is rare in those who have not started seeing their period or those in their menopause, as they have lower estrogen levels. 

Roughly 10% (190 million) of females globally are diagnosed with endometriosis. It is most common in those in their 30s and 40s, with the highest incidence among those ages 25–29.

The exact prevalence of this condition is not certain because some people with it either have no symptoms or experience mild symptoms, making them disregard seeing a doctor. Delay in diagnosis of endometriosis and limited healthcare specialists and treatment facilities, especially in low- and middle-income countries, are also factors.

What is endometriosis?

Endometriosis is a chronic, inflammatory disease that occurs when tissue similar to the one found in the inner parts of the uterus (called the endometrium) grows outside the uterus. Such endometrial tissues typically occur in other pelvic areas, such as the ovaries, fallopian tubes, and peritoneum. But they have also been found in areas outside the pelvic area, e.g., the intestine, lungs, and abdominal wall.

Endometriosis can affect a person’s quality of life and is commonly associated with severe pain during sexual intercourse, periods, bowel movements, and/or urination. 

Similar to the inner tissue that lines the endometrium, endometriotic tissues respond to the normal menstrual cycle—the proliferative, secretory, and menstrual phases of the cycle. This means they grow and shed during periods, just like the endometrium. However, without a way of flowing out through the vagina, they get trapped in the body.

This entrapment leads to inflammation, and the formation of thick scar tissues, which result in a series of symptoms people with the condition experience, especially pain. 

Types/stages of endometriosis

One of the most widely used and best-known systems of endometriosis classification is that developed by the American Society for Reproductive Medicine (ASRM). ASRM classified endometriosis into four stages depending on the location, the extent of endometriosis spread, and the depth of organ/tissue infiltration. They are as follows: 

  • Minimal (Stage I): This stage is characterized by small endometriotic lesions that are superficially embedded in the organ or tissue. There may be chances of inflammation in and around the pelvic cavity.
  • Mild (Stage II): This involves more widespread lesions than in stage I. Implants may be superficial or deep, with slight scar tissue.
  • Moderate (Stage III): Here, some of the endometriotic lesions may be found deep in the affected tissue, and there may be more dense scar tissue, resulting in a wider spread of the lesions. 
  • Severe (Stage IV): The most severe stage typically presents with many deep implants and the presence of endometriotic lesions, also called endometriomas or chocolate cysts, on the ovaries. There are more severe scar tissues in this stage, involving more areas than in stage III.

Is endometriosis the same as fibroids?

Fibroids and endometriosis have some common symptoms and are both benign (non-cancerous) growths of tissues found in the pelvic region, but they are different medical conditions. Fibroids are abnormal growths in the muscle layer of the uterus, while endometriosis is the growth of endometrial-like tissues outside the uterus. 

Notably, endometriosis and fibroids can occur simultaneously in an individual. A study showed that about 20% of patients with symptomatic fibroids had endometriosis, and 26% of patients with symptomatic endometriosis also had fibroids. One can also be a risk factor for the other. 

Causes of endometriosis

The exact cause of endometriosis is unknown; however, there are some factors that may contribute to its development. These factors include:

  • Genetic tendency: Genetics plays a vital role in the development of so many disease conditions, and endometriosis is not left out. It is believed that people who have relatives, especially immediate relatives, with endometriosis have a tendency to develop it later in life.
  • Retrograde menstruation: This is the backflow of a few volumes of menstrual blood through the fallopian tubes. It is suspected that the blood that flows into the pelvic cavity through the fallopian tubes carries endometrial tissues, which get embedded in another organ or tissue. Retrograde menstruation occurs in about 90% of people with uterus, but not all of them will develop endometriosis. 
  • Müllerian remnant hypothesis: Müllerian cells are cells found in a female baby growing in the womb, from which the female reproductive system develops. In some cases, remnants of these cells are found in some parts of the body after birth. It is believed that during puberty, hormones like estrogen may modify these cells into endometrial-like cell implants.
  • Cellular metaplasia: Cellular metaplasia is when cells change from one form to another. Cells outside the uterus can transform into endometrial-like cells and begin to grow. However, the exact mechanism isn't known. 
  • Endometrial cell transplant: In some cases, endometrial cells may be transported to other parts of the body through the blood vessels or tissue fluid (lymphatic) system. This may explain the presence of endometriotic tissues in places like the lungs and other organs outside the pelvic region.
  • Surgical scar implantation: After a surgery, such as a hysterectomy or C-section, endometrial cells may attach to a surgical incision on the skin. This may explain the presence of endometriosis tissues in the abdominal region in some people diagnosed with endometriosis.

Other risk factors include:

  • Starting your menstruation at an early age (early menarche)
  • Having menopause at an older age
  • Having a short menstrual cycle (less than 27 days)
  • Heavy menstruation that usually lasts longer than seven days
  • Having increased levels of estrogen than normal

Symptoms of endometriosis

In some people, endometriosis can cause little or no symptoms. However, in the majority of cases, the symptoms are severe and can affect all aspects of a person's life. Some of these symptoms include, but are not limited to:

Abnormal periods

Many people experience cramping during menstruation, but for those with endometriosis, the pain is more severe and can be incapacitating. In addition to this, they experience other symptoms like heavy and prolonged menstrual flow, headaches, fatigue, leg and back pain, and gastrointestinal discomforts such as nausea, vomiting, and diarrhea.

These symptoms are mostly consistent with each month's period.

Painful sexual intercourse (Dyspareunia)

Depending on where the endometriosis tissue is located, certain sex positions can cause more intense pain. If it occurs in the space between the vagina and the rectum—called the pouch of Douglas, it can cause pain and irritation during sex.

Nerve problems

Neuropathy is a nerve disease characterized by weakness, numbness, and pain from nerve damage in the affected part of the body. When an endometriotic lesion occurs close to a nerve, it can compress the nerve, causing damage to it. Neuropathy in endometriosis can manifest as chronic pelvic pain, back and leg pain, or hip pain. 

Gastrointestinal distress

Depending on the location of the lesions, endometriosis can cause gastrointestinal discomforts such as nausea, vomiting, constipation, and diarrhea. These may be worse during your period.

Fertility issues

Research has indicated that endometriosis is associated with infertility, especially in moderate to severe cases. About 4 in 10 people with infertility have endometriosis. This may be as a result of endometriotic lesions blocking the ovaries and fallopian tubes, preventing the release and transport of eggs.


Because the symptoms of endometriosis can mimic those of other diseases such as interstitial cystitis, its diagnosis can be complex and may take some time. Ways doctors diagnose endometriosis include:

  • History taking: This involves your doctor asking questions about your past and current state of health. They may ask about the symptoms you experience, how long you have experienced them, and their triggers. To help with your diagnosis, it is important that you give every detail of the symptoms. 
  • Pelvic examination: During a pelvic examination, your doctor will insert two fingers through your vagina to feel for any lesion and/or tenderness around the vagina or uterus. In minimal to mild cases, the lesions are small and might not be felt. You will most likely be sent for a radiological (imaging) investigation if the doctor suspects anything after this examination.
  • Radiological investigations: The two imaging tests that are mostly used are ultrasound, which uses sound frequencies to create an image of the internal body environment, and magnetic resonance imaging (MRI), which uses a magnetic field to create an image of the internal body environment. These tests don't definitively show you have endometriosis. However, they'll show an abnormality in the affected area, which will prompt a more definitive procedure.
  • Laparoscopic surgery and histology: This is a confirmatory diagnostic procedure for endometriosis. It is a minimally invasive surgery. A small cut will be made on your abdomen, near your navel, and an instrument, known as a laparoscope, inserted into your body to have a proper view of the areas affected. A sample of the tissue will then be collected and sent to the histology laboratory for proper assessment. The histology result will confirm whether you have endometriosis or not.

Is endometriosis curable?

Currently, no cure has been found for endometriosis, but there are treatment methods available to help relieve its symptoms. 

Treatment for endometriosis

The choice of treatment for endometriosis is based on individual symptoms and the individual's desire to conceive in the future.

If you have endometriosis, your treatment may include:

Pain relief medications

Drugs like non-steroidal anti-inflammatory drugs (NSAIDs), e.g., Ibuprofen, narcotics, e.g., pentazocine, and other pain-relieving drugs can help treat endometriosis pain.

Hormonal therapy

Some endometriosis symptoms are caused by fluctuations of the female sex hormones - estrogen and progesterone. Also, endometriosis responds to the level of estrogen in the body. Higher estrogen levels trigger the growth of endometriosis tissues, and vice versa. This is why hormonal therapy works for endometriosis treatment. 

Common hormonal therapies used include:

  • Birth controls: These can exist as pills, injectables, or patches. These medications help suppress the secretion of hormones by the ovaries. However, it affects fertility, making pregnancy nearly impossible. Nonetheless, you can get pregnant when you stop using them.
  • Gonadotropin-Releasing Hormone Agonists (GnRHa): This reduces the estrogen level in the body. It can cause side effects similar to those of menopause, e.g., hot flashes and vaginal dryness. Your doctor might add progestin-only pills to help combat these side effects.


Surgical procedures such as hysterectomy, deep excision surgery, and ablation and cauterization can be helpful for treating endometriosis. The aim of deep excision and ablation is to remove endometriotic lesions that are deep or superficial in a tissue or organ. Hysterectomy, on the other hand, means partially or totally removing the womb.

It is best to discuss each treatment option with your healthcare team. Ask questions about the pros and cons and work with them to decide the best option for you.

Other treatment methods that may provide relief are:

  • Diet: Red meat has been found to increase the estrogen level in the body, causing increased symptoms. Reducing the amount of red meat you eat while eating more of fruits and vegetables may be helpful if you have endometriosis.
  • Exercise: Exercise is beneficial to our bodies. It helps reduce the estrogen level, increase blood circulation, and maintain supplies of oxygen and nutrients to our cells. 

Does endometriosis go on its own?

Endometriosis often does not go away on its own. However, research has shown a reduction in the symptoms during pregnancy and possible shrinkage of the tissues in menopausal and postmenopausal females. This is attributed to the lower level of estrogen during these times. 

In pregnancy, progesterone is increased, lowering the estrogen level and reducing symptoms, whereas, in menopause, a drastic reduction in estrogen level causes possible shrinkage and a reduction of symptoms.

When to see the doctor

Knowing how your body functions is the first step to detecting when something has changed. If you notice any of the above-mentioned symptoms, especially if they persist for a long time, it's best to visit your doctor. 

Your doctor will most likely refer you to a gynecologist for a proper examination and diagnosis. Early diagnosis and treatment help reduce the severity of this condition. 


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