The endometrium is the type of tissue that lines the inside of the uterus. In endometriosis, tissue similar to the endometrium grows outside the uterus. Endometriosis can be a painful condition, especially during menstruation, and endometriosis can impair fertility. Research into the patient experience of this condition has suggested that we redefine endometriosis as a syndrome that includes both these ectopic uterine tissue deposits and the symptoms they cause, since some people with ectopic endometrial tissue don’t experience any symptoms.^[1]

The main symptoms are pain and infertility.^[2][1] Some of the common symptoms that people with endometriosis may experience are: Painful periods (dysmenorrhea); pain during or after sex (dyspareunia); pain while urinating (dysuria) or defecating (dyschezia); unusually heavy periods or bleeding between periods; infertility; and fatigue, diarrhea, constipation, bloating or nausea, especially during menstrual periods. It’s possible for people with endometriosis to experience all, some, or none of these symptoms. Some people with endometriosis may experience atypical symptoms, like back pain, chest pain, leg pain, rectal bleeding, or acid reflux, and this could be related to inflammation or to the location of the lesions.^[3]

Endometriosis has a wide symptom range, and needs to be diagnosed by a doctor; the gold standard for diagnosis is laparoscopy (minimally invasive surgery), although nonsurgical diagnostic tools are being investigated. In terms of imaging, MRI is showing the most positive results, although more studies are needed before it can replace surgical diagnosis. Transvaginal ultrasound may also be useful for endometriosis involving the rectum and sigmoid colon.^[4] Blood markers could also be used for diagnosis in the future, although the appropriate marker hasn’t yet been found. Anti-endometrial autoantibodies, interleukin 6 (IL-6), and cancer antigen 125 (CA 125) have been considered, but are not accurate enough to replace the current diagnostic standard.^[5]

Endometriosis is a chronic condition requiring long-term treatment which focuses on symptom management. Symptoms can be managed medically through surgery to remove endometriotic tissues, and through long-term medication for hormonal management. Hormone treatment, in the form of tablets, skin patches or implants, may effectively reduce pain symptoms, but may not be appropriate in patients with infertility, or in women who are trying to become pregnant. Endometriosis-impaired fertility can be addressed by assisted reproduction techniques, such as in vitro fertilization (IVF).^[6] Although surgery isn’t considered a cure (because endometriotic tissue may return after surgery), it can reduce painful symptoms in the short term, and hormonal treatment can delay the tissue’s regrowth.^[7]

Several vitamins and supplements have been studied, including vitamin D,^[8] melatonin,^[9] and vitamins E and C. Vitamin E, with or without vitamin C, seems to improve pain symptoms. Vitamin D also improves pain symptoms to a lesser extent. Both effects are small, but given their good safety profiles, these supplements are worth considering in conjunction with other medical interventions.^[10] Melatonin has limited evidence to support its use, but it might improve pain symptoms, sleep quality, and mood symptoms in people with endometriosis.^[11]

Multiple studies have investigated the relationship between diet and endometriosis. There is weak evidence that a healthy diet, with reduced alcohol intake and increased physical activity, is associated with a lower risk of getting endometriosis.^[12] A diet high in fruit, particularly citrus fruit, might lower the risk for endometriosis.^[13]

Some people may find that some of their symptoms of endometriosis, such as painful menstruation, can be non-medically managed. Some people with endometriosis develop chronic pelvic pain, which may be manageable with pelvic physiotherapy and myofascial trigger point dry needling.^[6]

The endometrium is the lining of the uterus. Endometriosis is caused by endometrium-like cells growing outside the uterus, usually accompanied by inflammation.^[12] Researchers haven’t yet pinned down exactly why this happens.^[14]