Endometriosis is a long-term (chronic) condition, usually accompanied by inflammation, in which tissue similar to the lining of the uterus (endometrium) is found outside the uterus. This tissue is mostly found in the pelvis: the lining of the abdomen and pelvis (peritoneum), the ovaries, the fallopian tubes, the space behind the uterus and the outer surfaces of the uterus, bladder or bowel are the most common sites. Less commonly, it can be found outside the pelvis, for example in old surgical scars. The condition is influenced by the hormone estrogen, so it is most often seen during the reproductive years. It is estimated to affect about 10% of women of reproductive age.
Endometrioma (chocolate cyst)
A cyst that endometriosis forms in the ovary is called an endometrioma; it is also commonly known as a chocolate cyst. Endometriomas can cause pain and difficulty getting pregnant. Other types of ovarian cyst and the general features of cyst surgery (cystectomy) are described on the Ovarian Cysts page.
Symptoms and who is affected
Symptoms vary from person to person:
- Period pain that may get worse over time and affects daily life
- Pelvic pain that may change with the menstrual cycle or be constant
- Deep pain during or after sexual intercourse
- Painful bowel movements or painful urination, especially during periods; less commonly, blood in the stool or urine at this time
- Digestive complaints such as bloating and constipation
- Fatigue
- Difficulty getting pregnant
The severity of pain does not always match the extent of the disease: someone with extensive disease may have few complaints, while someone with limited disease may have marked pain. Some people have no symptoms at all, and the condition is noticed during investigations for difficulty getting pregnant or during surgery done for another reason.
Endometriosis can occur at any age from puberty to menopause. It is more common in people whose mother or sister has endometriosis. Starting periods at a very young age, short menstrual cycles and differences in the reproductive organs present from birth are also among the factors that increase the likelihood.
Diagnosis
Assessment begins with a detailed history of the complaints and an examination. Transvaginal ultrasound is the main imaging method for showing endometriomas and deep endometriosis; MRI is used for extensive disease involving the bladder or bowel. Small, superficial lesions on the lining of the abdomen, however, often cannot be seen on imaging, so a normal examination and ultrasound do not rule out endometriosis. Blood tests such as CA-125 are not used to diagnose endometriosis.
In the past, laparoscopy was considered essential for diagnosis. Current guidelines accept that treatment can be started when endometriosis is suspected on the basis of the complaints and imaging findings. Laparoscopy is considered when complaints persist despite normal imaging, when medical treatment has not worked or is unsuitable, or when diagnosis and treatment are planned in the same operation. A tissue sample taken from lesions seen at laparoscopy is examined by pathology; a normal result does not entirely rule out the disease.
Because the symptoms can be confused with other conditions (for example, bowel or urinary problems), years often pass between the start of symptoms and diagnosis.
Treatment options
Treatment is planned according to the complaints, the location and extent of the disease, age and the wish for pregnancy. There is no treatment that definitively eliminates endometriosis; the aims of treatment are to relieve pain, protect quality of life and support the chance of pregnancy in those who wish to conceive. Endometriosis that causes no complaints and is found incidentally during surgery for another reason usually does not need treatment.
- Pain relievers: non-steroidal anti-inflammatory drugs such as ibuprofen, or acetaminophen (paracetamol), may be used alone or with other treatments to relieve pain. These medicines do not treat the disease itself.
- Hormonal treatment: the combined contraceptive pill (or ring or patch), progestin-only medicines, a hormone-releasing intrauterine device or a contraceptive implant can reduce pain by suppressing the menstrual cycle and are first-line options. When these are not sufficient, GnRH analogs may be used as second-line treatment; because these medicines can cause menopause-like side effects such as hot flashes and reduced bone density, they are often given together with low-dose add-back hormone therapy. Most hormonal medicines prevent pregnancy while they are being used; they do not harm fertility in the long term. Complaints often return when the medicine is stopped.
- Surgery: unless there is a reason against it, surgery for endometriosis is performed laparoscopically (keyhole surgery). During the operation, endometriosis lesions are removed or destroyed, and adhesions are divided. In surgery for an endometrioma, removing the cyst wall (cystectomy) reduces recurrence of the cyst and of pain more than simply draining and coagulating the cyst; on the other hand, it may affect the ovarian reserve more. Operations for deep endometriosis involving the bowel, bladder or ureter are more extensive; it is recommended that they are performed by teams experienced in this field, including general surgery and urology specialists when needed.
For people who do not wish to become pregnant and for whom other treatments have not been sufficient, hysterectomy (removal of the uterus) together with removal of all visible endometriosis lesions may be considered. Hysterectomy does not necessarily mean that the complaints or the disease will go away completely. Whether the ovaries are also removed is decided taking into account the long-term effects of early menopause.
There is not enough evidence to show the benefits and harms of non-medical approaches such as dietary changes, acupuncture, physical therapy or herbal products for endometriosis pain. In long-standing pain, pain management and psychological support may also be part of care.
Endometrioma and ovarian reserve
Endometriomas and surgery for them can reduce the egg reserve of the ovary. This effect is more marked when there are cysts in both ovaries and when cyst surgery is repeated. For this reason, the decision to operate takes into account the size and appearance of the cyst, the complaints, age, pregnancy plans and ovarian reserve tests such as AMH. When surgery is not performed, the cyst can be monitored with regular ultrasound check-ups. For people with extensive ovarian endometriosis, the benefits and limitations of fertility preservation options such as egg freezing can be discussed; the true benefit of these options in endometriosis is not yet known.
Wishing to become pregnant
Many women with endometriosis can become pregnant naturally; for some, pregnancy takes longer or is more difficult. In extensive disease, adhesions can impair the function of the fallopian tubes. If there is difficulty getting pregnant, the assessment is carried out as a couple, and the approach is planned taking into account age, complaints, the extent of the disease, ovarian reserve and other fertility factors.
- Because hormonal medicines do not improve fertility, they are not used for this purpose in people who wish to become pregnant.
- In mild (stage I–II) endometriosis, laparoscopic removal of lesions in people who have not been able to conceive may increase the chance of natural pregnancy.
- In people planning IVF, surgery for an endometrioma is not routinely recommended solely to improve the outcome of treatment; no such benefit has been shown, and surgery may reduce the ovarian reserve. Surgery is considered in situations such as pain or a cyst making it difficult to reach the follicles during egg collection.
- If tubal function is impaired, if there is a male factor or if other methods have not worked, assisted reproduction treatments are considered. These treatments are carried out in licensed assisted reproduction centers.
Pregnancy does not always relieve symptoms or stop the disease from progressing; for this reason, becoming pregnant solely to treat endometriosis is not recommended.
Recurrence and the long term
Endometriosis can return after treatment. Complaints and cysts may also recur after surgery; the more extensive the disease, the more likely it is to return. After surgery for an endometrioma, long-term hormonal treatment (for example, the combined pill or a hormone-releasing intrauterine device) is recommended for people not planning a pregnancy in the near future, to reduce recurrence of the cyst and the complaints. For recurring complaints, medical and surgical options are reassessed.
After menopause, complaints often ease because the ovaries produce less estrogen; however, the disease can remain active after menopause.
Possible risks and limitations
Hormonal medicines may cause irregular or breakthrough bleeding, headaches and other side effects that vary with the medicine; each medicine has situations in which it cannot be used, and the choice is made individually with this in mind. Medicines may not relieve pain sufficiently for everyone. General risks of surgery include bleeding, infection, blood clots, problems related to anesthesia and injury to the bowel, bladder or ureter; these risks are higher in operations for deep endometriosis involving the bowel or bladder. Ovarian surgery can reduce the ovarian reserve. Surgery may not remove lesions that cannot be seen or removed, and complaints may return. The general features and risks of laparoscopic and open surgery are described on the Laparoscopic (Keyhole) and Open Surgery page.