What happens in the body of a woman with endometriosis?
The endometrium (lining of the uterus) is a unique tissue that renews itself every month without scarring. This is essential for a woman’s health and fertility. However, with endometriosis, a fundamental change occurs – endometrial-like tissue appears outside the uterus, for example on the ovaries, fallopian tubes, bladder or intestines¹.
These deposits respond to the hormonal cycle in the same way as normal mucous membrane, but instead of natural shedding, they undergo:
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chronic inflammation
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scarring (fibrosis)
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formation of new blood vessels and nerve endings
The result is chronic pain, often accompanied by fertility problems and an overall deterioration in quality of life.
There are three main types of endometriotic lesions:
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Superficial peritoneal lesions – inflamed or scarred areas on the peritoneum
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Endometriomas – blood-filled cysts on the ovaries, nicknamed “chocolate cysts”
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Deep infiltrating endometriosis – deposits growing between organs such as the uterus, bladder and intestines
Rarely, foci can also appear outside the pelvis – for example, in the lungs, diaphragm, on the skin, or even in the brain.
Find endometriosis care here .
🧠 Endometriosis = neuroinflammatory disease
The latest research shows that endometriosis is not just a gynecological disease, but a complex neuroinflammatory condition:
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The bearings create their own nerve endings, which amplifies painful sensations³.
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The immune system amplifies pain signaling, leading to a chronic pain state⁴.
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There is so-called central sensitization – the nervous system becomes more sensitive to painful stimuli⁵.
This mechanism explains why:
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Pain can be significant even with small lesions or even when they are not visible on examination.
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Endometriosis is often associated with other problems (fatigue, irritable bowel syndrome - IBS, migraines).
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Chronic pain affects not only the body, but also brain function and psychological state.
💥 Why is pain often not related to the size of the bearings?
Many women with endometriosis hear the phrase: "Everything is fine on the ultrasound." Yet these women experience severe pain.
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Studies confirm that the size or number of lesions often does not correspond to the intensity of pain⁶.
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Some women have extensive lesions without symptoms, while others experience significant pain without detectable lesions.
Pain in endometriosis is influenced by multiple factors:
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Inflammation in the tissues
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Increased growth of nerve endings
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Immune cell activity
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Increased hormonal sensitivity
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Presence of other diseases (e.g. migraine, IBS)
What are the typical symptoms of endometriosis?
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Very painful menstruation
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Sharp pain in the lower abdomen even outside of menstruation
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Significant mood swings that are difficult to control
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Chronic, intense fatigue
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Digestive problems (painful bowel movements, bloating)
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Pain during or after sexual intercourse
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Problems getting pregnant⁷
Diagnosis of endometriosis includes:
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Laparoscopy – surgical examination to identify superficial lesions.
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Ultrasound examination – especially for diagnosing ovarian cysts (endometriomas).
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MRI – magnetic resonance imaging used mainly for deep infiltrating endometriosis⁸.
However, neither method is 100% accurate, with an average diagnosis of endometriosis taking 8 years ⁹. There is currently no reliable blood test for diagnosing endometriosis.
Clinical studies and expert resources:
¹ Bulun, S.E., et al. (2019)
Endometriosis.
https://pubmed.ncbi.nlm.nih.gov/30787484/
² Chapron, C., Marcellin, L., et al. (2019)
Deep infiltrating endometriosis.
https://pubmed.ncbi.nlm.nih.gov/30891937/
³ Morotti, M., Vincent, K., & Becker, C. M. (2017)
Mechanisms of pain in endometriosis.
https://pubmed.ncbi.nlm.nih.gov/28692978/
⁴ McKinnon, B., et al. (2015)
Inflammation and nerve fibers in endometriosis.
https://pubmed.ncbi.nlm.nih.gov/26132942/
⁵ Stratton, P., & Berkley, K. J. (2011)
Chronic pelvic pain and central sensitization.
https://pubmed.ncbi.nlm.nih.gov/21751007/
⁶ Vercellini, P., et al. (2007)
Relationship between lesion characteristics and pain in endometriosis.
https://pubmed.ncbi.nlm.nih.gov/17403024/
⁷ Zondervan, KT, Becker, CM, & Missmer, SA (2020)
Endometriosis: pathogenesis and clinical consequences.
https://pubmed.ncbi.nlm.nih.gov/32929266/
⁸ Bazot, M., & Daraï, E. (2017)
Diagnosis of deep endometriosis: Clinical examination, ultrasonography, magnetic resonance imaging.
https://pubmed.ncbi.nlm.nih.gov/29157559/
⁹ Hudelist, G., et al. (2012)
Diagnostic delay for endometriosis.
https://pubmed.ncbi.nlm.nih.gov/22776534/
