What is endometriosis?

Endometriosis is a chronic disease in women where tissue similar to the lining of the uterus (endometrium) is found in lesions outside of the uterus. These lesions are most commonly located in the ovaries, uterus, uterine ligaments, fallopian tubes, inner lining of the pelvic peritoneum, and less commonly in the intestines, surgical scars, urinary tract, cervix and vagina. In theory, endometriotic lesions can occur in any tissue.

The tissue affected by endometriosis behaves similarly to the lining of the uterine cavity. Therefore, under the influence of female hormones, there is growth and partial detachment of these lesions in various phases of the menstrual cycle, causing bleeding.

Who is at risk for endometriosis?

Endometriosis most often occurs in women of reproductive age who have periods. In rare cases, symptoms may also affect patients when they reach menopause (the end of menstrual cycles). Rarely, endometriosis can occur even before menarche (the first menstrual period). The exact prevalence of the disease is unknown, but it is estimated that about 2-10% of women of reproductive age are affected by endometriosis. Approximately half of women with fertility issues have endometriosis.

What complaints does endometriosis cause?

20-25% of women with endometriosis have no symptoms. However, complaints can be severe and negatively impact quality of life. Key complaints include the following:

Pain.  73% of women with endometriosis experience pelvic pain. The pain typically occurs or intensifies cyclically, it intensifies one to two days before menstruation, lasts throughout the period and, in some women, also a few days after the period. The pain is caused by the cyclical bleeding of endometriotic lesions, leading to tension in surrounding tissues and chronic inflammation. Eventually, adhesions (fibrous bands) may form between organs affected by endometriosis, which can cause constant pain.

Infertility.  25% of women with endometriosis experience difficulties conceiving. This is related to adhesions in the fallopian tubes and ovaries as well as persistent inflammatory processes. Fertility treatment is often necessary to get pregnant.

Other complaints. Less commonly, digestive and urinary disorders, painful intercourse, chronic fatigue, lower back pain and heavy menstrual bleeding may occur.

What are the types of endometriosis?

Superficial endometriosis. Lesions are typically on the inner lining of the pelvic peritoneum or superficially on organs.

Endometriomas. The most commonly diagnosed form – a cyst that develops from ovarian endometriosis, known as an endometrioma. These cysts have a characteristic chocolate-like brown content. In one-third of cases, such cysts are found in both ovaries.

Deep endometriosis. Rare and the most serious form of endometriosis,

involving various abdominal organs (such as the bowel, bladder, ureters).


Endometriosis is often difficult to diagnose as symptoms are nonspecific and vary among women. Doctors usually suspect endometriosis based on the woman’s complaints.  Sometimes, it may be an incidental finding during surgery.

The main diagnostic tools for endometriosis are as follows:

Gynaecological ultrasound. Used to assess the condition of the uterus and ovaries as well as adjacent tissues. The most common ultrasound finding is an endometrioma (a cyst resulting from ovarian endometriosis), which occurs in 25% of patients with endometriosis. A typical cyst with typical complaints gives reason to suspect endometriosis.

MRI or magnetic resonance imaging. Used to assess the wider spread of endometriotic lesions. MRI is indicated only in specific cases to clarify the diagnosis.

Laparoscopy. Allows the doctor to see whether there are characteristic lesions of endometriosis in the abdominal cavity and, if necessary, take a tissue sample (biopsy) for examination. A biopsy provides definitive confirmation of the diagnosis, although it is not always necessary in the presence of other highly typical symptoms.


Endometriosis is a chronic disease that cannot be cured. The goal of treatment is to reduce pain and other symptoms, enhance the likelihood of conception and improve the woman’s quality of life.

Treatment options:

Pain medications. These relieve the pain that worsens during menstruation and reduce the inflammatory response.   Pain medications are intended for short-term use during severe pain episodes.

Hormone treatment. These affect hormone-sensitive endometriotic lesions, reducing their size to a certain extent and preventing the spread of the disease, make menstruation less painful and reduce menstrual bleeding, and help maintain control over the disease. Hormone treatment can be used for an extended period.

If a woman is not currently planning to conceive, hormonal contraceptives (combined hormonal methods, progestin-only pills, hormonal intrauterine devices, implants) are often suitable for treatment.

Sometimes other hormonal preparations may be used for treatment. If necessary, your doctor will explain this to you.

Surgery. This is usually laparoscopic, allowing the doctor to release adhesions caused by endometriosis between organs and remove endometriotic lesions and the capsule of an endometriotic cyst. Open surgery is rarely necessary.


Approved by the decision of the Care Quality Commission of East Tallinn Central Hospital on 10.01.2024 (protocol no. 1-24)