[3] Other causes of similar symptoms include pelvic inflammatory disease, irritable bowel syndrome, interstitial cystitis, and fibromyalgia.

[41][42] A 20-year study involving 12,000 women with endometriosis found that individuals under 40 are three times more likely to develop heart problems compared to their healthy peers.

[71] This correlation is mediated by an immune system overload in the context of retrograde menstruation, in which it fails to detect and kill cells that come outside of the vaginal environment.

They, in turn, secrete factors (such as the pro-inflammatory cytokine interleukin 8) that help create an inflammatory environment, ultimately favoring the proliferation and adhesion of endometrial cells.

[53] The main theories for the formation of the ectopic endometrium-like tissue include retrograde menstruation, Müllerianosis, coelomic metaplasia, vascular dissemination of stem cells, and surgical transplantation were postulated as early as 1870.

[53][73][75] Proofs in support of the theory are based on retrospective epidemiological studies that an association with endometrial implants attached to the peritoneal cavity, which would develop into endometrial lesions and retrograde menstruation; and the fact that animals like rodents and non-human primates whose endometrium is not shed during the estrous cycle don't develop naturally endometriosis contrary to animals that have a natural menstrual cycle like rhesus monkeys and baboons.

Many health care practitioners never encounter this defect, and due to the flu-like symptoms it is often misdiagnosed or overlooked until multiple menstrual cycles have passed.

[97] Risk factors for scar endometriosis include previous abdominal surgeries, such as a hysterotomy or cesarean section, or ectopic pregnancies, salpingostomy puerperal sterilization, laparoscopy, amniocentesis, appendectomy, episiotomy, vaginal hysterectomies, and hernia repair.

Diaphragmatic endometriosis is rare, almost always on the right hemidiaphragm, and may inflict the cyclic pain of the right scapula (shoulder) or cervical area (neck) during a menstrual period.

[99] Definitive diagnosis is based on the morphology (form and structure) of the pelvic region, determined by observation (surgical or non-invasive imaging), classified into four different stages of endometriosis.

During a laparoscopic procedure, lesions can appear dark blue, powder-burn black, red, white, yellow, brown or non-pigmented.

[117] By extending the ultrasound assessment into the posterior and anterior pelvic compartments a sonographer is able to evaluate structural mobility and look for deep infiltrating endometriotic nodules.

[118] Better sonographic detection of deep infiltrating endometriosis could reduce the number of diagnostic laparoscopies, as well as guide disease management and enhance patient quality of life.

[110] A 2020 article recommended administering an anti-spasmodic agent (i.e. hyoscine butylbromide) and a big glass of water (if the bladder is empty), and scanning in the supine position with an abdominal strap, for better image quality.

[121] Another review in 2011 identified several putative biomarkers upon biopsy, including findings of small sensory nerve fibers or defectively expressed β3 integrin subunit.

[123] It has been postulated a future diagnostic tool for endometriosis will consist of a panel of several specific and sensitive biomarkers, including both substance concentrations and genetic predisposition.

[128] Limited evidence indicates that the use of combined oral contraceptives is associated with a reduced risk of endometriosis, as is regular exercise and the avoidance of alcohol and caffeine.

[132] In the reproductive years, endometriosis is merely managed: the goal is to provide pain relief, to restrict progression of the process, and to restore or preserve fertility where needed.

A 2020 Cochrane systematic review found that for all types of endometriosis, "it is uncertain whether laparoscopic surgery improves overall pain compared to diagnostic laparoscopy".

[113] Treatment consists of the ablation or excision of the endometriosis, electrocoagulation,[136] lysis of adhesions, resection of endometriomas, and restoration of normal pelvic anatomy as much as is possible.

[175] The advantages of physical therapy techniques are decreased cost, absence of major side-effects, it does not interfere with fertility, and near-universal increase of sexual function.

[178] Criteria that are commonly used to establish a diagnosis include pelvic pain, infertility, surgical assessment, and in some cases, magnetic resonance imaging.

[185] The rate of recurrence has been shown to increase with time from surgery and is not associated with the stage of the disease, initial site, surgical method used, or post-surgical treatment.

[187] Historically, women with these symptoms were treated with leeches, straitjackets, bloodletting, chemical douches, genital mutilation, pregnancy (as a form of treatment), hanging upside down, surgical intervention, and even killing due to suspicion of demonic possession.

[187] The fact that Hippocratics were recommending changes in marriage practices due to an endometriosis-like illness implies that this disease was likely common, with rates higher than the 5-15% prevalence that is often cited today.

A study done in Puerto Rico in 2020 found that health care and interactions with friends and family related to discussing endometriosis were affected by stigma.

[248] The most common finding was a referral to those expressing pain related to endometriosis as "changuería" or "changas", terms used in Puerto Rico to describe pointless whining and complaining, often directed at children.

[248] The existing stigma surrounding women's health, specifically endometriosis, can lead to patients not seeking diagnoses, lower quality of healthcare, increased barriers to care and treatment, and negative reception from members of society.

[250][251] Widespread awareness campaigns, developments and implementations aimed to multilevel anti-stigma organizational and structural changes, as well as more qualitative studies of the endometriosis stigma, help to overcome the harm of the phenomenon.

[252] Preliminary research on mouse models showed that monoclonal antibodies, as well as inhibitors of MyD88 downstream signaling pathway, can reduce lesion volume.