What Endometriosis Can Affect Beyond the Pelvis: One Diagnosis Should Not End the Investigation

Understanding Whole-Body Symptoms, Nervous System Sensitization, and the Pelvic Pain Overlap Spectrum

The reality is that endometriosis is a complex, chronic inflammatory disease that impacts the entire body; and understanding its impact requires looking beyond the pelvis.

Endometriosis Is More Than a Reproductive Disorder

Endometriosis occurs when tissue resembling the endometrium, or uterine lining, grows outside the uterus. These lesions can provoke inflammation, fibrosis, adhesions, and changes in how the nervous system processes pain. Although endometriosis is commonly found in the pelvis, it can also affect structures such as the bowel, bladder, diaphragm, and, less commonly, the thoracic cavity.
Symptoms may include:

• Painful menstrual periods
• Persistent pelvic or abdominal pain
• Pain with bowel movements or urination
• Pain with intercourse or sexual activity
• Digestive disturbances
• Fatigue and sleep disruption
• Infertility
• Cyclic shoulder, chest, or upper abdominal pain in some cases of extrapelvic disease

Importantly, the severity of pain does not necessarily correspond to the stage or apparent extent of endometriosis. Someone with relatively limited visible disease may experience severe pain, while another person with extensive lesions may have fewer symptoms. This is one reason why endometriosis cannot be understood solely through imaging, surgical staging, or reproductive symptoms. [1, 2]

1. The Nervous System: When Pain Becomes More Complex

One of the most important concepts in understanding persistent endometriosis-related pain is sensitization. Pain is not simply a direct measurement of tissue damage. It is an experience generated and influenced by the nervous system. In endometriosis, several mechanisms may contribute to pain.

• Peripheral sensitization occurs when inflammatory mediators and other changes near endometriotic lesions increase the sensitivity of local nerve endings.
• Central sensitization involves increased responsiveness within the central nervous system. Over time, pain signals may be amplified, and sensations that would ordinarily be tolerable can become painful.
• Cross-organ “talk” and sensitization describes how pain or inflammation associated with one pelvic organ may influence pain processing in another, partly because pelvic organs share overlapping neural pathways.

For example, the bowel, bladder, reproductive organs, and pelvic floor can have interacting sensory pathways. This helps explain why a woman with endometriosis may experience bowel or bladder symptoms even when those organs are not directly infiltrated by endometriotic lesions. It is important to distinguish these mechanisms from active disease.

Central sensitization does not mean endometriosis is imaginary, psychological, or simply a nervous system problem. And identifying sensitization must never be used as a reason to dismiss the possibility of persistent or inadequately treated endometriotic disease.

Both active pathology and altered pain processing can exist at the same time. [2, 3]

2. The Pelvic Overlap Spectrum: Why Endometriosis Rarely Exists in Isolation

Understanding Pelvic Overlap Spectrum Syndrome (POSS)

The Pelvic Overlap Spectrum Syndrome (POSS) framework encourages us to look beyond a single diagnosis and consider the interactions between multiple body systems. Rather than asking only, “What diagnosis does this patient have?” we also ask:

• How are these symptoms connected?
• Which body systems are contributing?
• What is driving the pain or dysfunction?
• Are there overlapping conditions that have been overlooked?

POSS considers relationships among the musculoskeletal, nervous, connective tissue, gastrointestinal, urologic, gynecologic, respiratory, and vocal systems. For example, someone with endometriosis may also have generalized joint hypermobility, pelvic floor muscle dysfunction, constipation, and altered breathing mechanics. Although these conditions do not necessarily share a single cause, they can influence how someone moves, manages pressure, processes pain, and experiences everyday activities.

How Does POSS Differ From Chronic Overlapping Pain Conditions?

Researchers have identified a group of disorders known as chronic overlapping pain conditions (COPCs).

These include endometriosis, irritable bowel syndrome, interstitial cystitis/bladder pain syndrome, vulvodynia, fibromyalgia, migraine, and other persistent pain disorders. COPCs can share features such as altered pain processing, heightened sensitivity, sleep disturbances, and overlapping symptoms. [3–5] The Pelvic Overlap Spectrum builds on the clinical need to recognize these intersections while broadening the assessment to include additional contributing systems, such as:

• Connective tissue: Hypermobility and associated movement or tissue-support challenges.
• Autonomic nervous system: Symptoms involving heart rate, orthostatic tolerance, and other autonomic functions.
• Respiratory system: Breathing patterns, diaphragm coordination, and pressure management.
• Musculoskeletal system: Hip and spinal function, pelvic floor coordination, and myofascial pain.
• Voice and jaw: Functional relationships involving the jaw, respiratory system, and pelvic floor.

Not every person with endometriosis experiences these problems, and their presence does not establish that endometriosis caused them. Instead, the POSS framework helps clinicians investigate potentially interacting contributors without assuming that all symptoms must come from one disease.

Why This Changes Treatment

At Garner Pelvic Health, our approach to Pelvic Overlap Spectrum Syndrome includes looking at how the entire body functions. An individualized assessment may consider pelvic floor function, hip and spinal mobility, breathing mechanics, core and diaphragm coordination, hypermobility, nervous system responses, and other relevant clinical factors.

The goal is not simply to identify more diagnoses. The goal is to understand why symptoms persist, which factors are modifiable, and how to build a coordinated treatment plan that addresses the whole person. For women with endometriosis who have spent years receiving fragmented care, this broader perspective can be especially valuable.

Learn More About the Pelvic Overlap Spectrum

Read more about our clinical approach to Pelvic Overlap Spectrum Syndrome at Garner Pelvic Health.

The framework is also discussed through ESSI, which explores complex pelvic pain and overlapping conditions, and also provides expert endometriosis excision.

3. Endometriosis and the Gastrointestinal System

Digestive symptoms are among the most frequently overlooked concerns in women with endometriosis. Patients commonly report:

• Abdominal bloating, sometimes called “endo belly”
• Constipation or diarrhea
• Painful bowel movements
• Abdominal cramping
• Nausea
• Changes in bowel habits around menstruation
• Pain or pressure in the rectal region

These symptoms may arise through several pathways. Endometriosis can involve the bowel directly, particularly in cases of deep endometriosis. However, digestive symptoms may also occur without bowel lesions. Inflammation, pelvic floor muscle dysfunction, altered visceral sensitivity, and coexisting IBS can contribute to gastrointestinal discomfort.

The bowel and reproductive organs share neural pathways, meaning painful input from one region can influence how another region responds. This is why treating gastrointestinal symptoms as entirely separate from pelvic pain may overlook important connections.

At the same time, symptoms should not automatically be attributed to endometriosis. Gastrointestinal disorders deserve their own evaluation, especially when symptoms are new, progressive, or accompanied by bleeding, unexplained weight loss, or other concerning changes. [2, 3, 5]

4. Fatigue: One of the Most Underrecognized Symptoms

For many women, fatigue is as disruptive as pain. And it is not simply feeling tired after a difficult day. Endometriosis-associated fatigue can be persistent, disproportionate to activity, and deeply disruptive to work, relationships, exercise, and daily life.

In a multicenter study of 1,120 women, researchers found frequent fatigue in approximately 51% of women with confirmed endometriosis, compared with 22% of women in the control group. Fatigue was associated with factors including pain, insomnia, depression, and occupational stress. The study did not establish that these factors directly caused fatigue. [6]

Women with endometriosis may also experience sleep disruption, heavy menstrual bleeding, or coexisting medical conditions that contribute to low energy. Fatigue deserves medical assessment rather than being dismissed as an inevitable part of living with endometriosis.

Depending on the individual’s symptoms, that may include screening for anemia or iron deficiency, sleep disorders, endocrine conditions, medication effects, or other health concerns. Fatigue is not a character flaw. It is a symptom that deserves investigation and appropriate care.

5. The Musculoskeletal System and Pelvic Floor

One of the most clinically important yet frequently missed components of endometriosis care is the musculoskeletal system. Persistent pelvic pain can influence muscle recruitment, movement strategies, breathing patterns, and the ability to relax the pelvic floor. Over time, some individuals develop pelvic floor myofascial pain, characterized by tenderness, increased muscle activity or guarding, and impaired coordination. 

Symptoms may include:

• Pain with penetration or sexual activity
• Difficulty relaxing during bowel movements
• Urinary urgency or discomfort
• Pain involving the hips, low back, buttocks, or pelvis
• Difficulty tolerating exercise or prolonged sitting
• Persistent pain even after medical or surgical treatment

These musculoskeletal symptoms may coexist with endometriotic lesions, sensitization, and other chronic pain conditions. Importantly, pelvic floor dysfunction is not the same thing as endometriosis.

6. Why Multidisciplinary Care Matters

Endometriosis is rarely best managed through a single treatment or specialty. This is especially true when symptoms extend beyond the reproductive system or when multiple overlapping pain conditions are present. A multidisciplinary approach may involve:

• Endometriosis specialists and gynecologists to evaluate disease, discuss hormonal or nonhormonal treatment options, assess fertility concerns, and consider surgery when appropriate.
• Pelvic health physical therapists to evaluate pelvic floor dysfunction, musculoskeletal pain, movement limitations, and other rehabilitation needs, as well as address intervention through advanced care and services including FILM (Functional, Integrative, and Lifestyle Medicine), the Voice to Pelvic Floor method, and musculoskeletal ultrasound imaging. 
• Gastroenterologists to assess persistent digestive symptoms, possible IBS, and other bowel disorders.
• Urologists or urogynecologists to evaluate urinary pain, urgency, frequency, or bladder pain syndrome.
• Pain medicine clinicians and/or physiatrists to assess complex pain mechanisms and additional treatment options when needed.
• Mental health professionals experienced in persistent pain and medical trauma and gaslighting to support coping, relationships, and the psychological burden of chronic illness without suggesting that the disease is psychological.

Additional professionals may be helpful depending on nutritional concerns, fatigue, sleep, or other coexisting conditions. Multidisciplinary care should also be coordinated. Sending a woman to six different specialists who never communicate is not the same as providing comprehensive treatment. Current clinical literature emphasizes identifying and addressing peripheral disease, pelvic myofascial pain, chronic overlapping pain conditions, and sensitization when present. [1, 5]

The best care does not force every symptom into one diagnosis. It investigates how multiple conditions may be contributing to the patient’s experience.

7. What I Wish More Women Knew About Endometriosis

There are several things I wish every woman understood about this disease:

• First, severe menstrual pain should not be normalized or dismissed.
• Second, endometriosis may affect much more than menstruation. Digestive problems, bladder symptoms, neurological symptoms, fatigue, sexual pain, and other persistent symptoms all deserve investigation.
• Third, a normal ultrasound or MRI does not necessarily exclude endometriosis, particularly superficial disease. [1]
• Fourth, persistent pain after endometriosis treatment does not automatically mean the disease has returned, but neither does it prove the disease is gone. Both ongoing pathology and overlapping pain contributors deserve consideration.

• Fifth, pelvic floor physical therapy is a critical part of management and recovery as part of a team approach to care.
• Sixth, expert surgical excision (not ablation) is not the end of endometriosis, it’s the beginning of the journey. Pelvic floor physical therapy should always follow excision, no matter how minor the surgery. 
• And finally, women deserve clinicians who take your whole body health, and the entire clinical picture, seriously.

Too many women spend years trying to connect symptoms that have been repeatedly separated into different diagnoses, appointments, and medical specialties. Often, they have already recognized that something is wrong. What they need is a healthcare system willing to investigate it.

The Bottom Line: Endometriosis Requires Whole-Person Care

Endometriosis is a complex disease with effects that can extend well beyond the pelvis. Its impact may involve inflammation, the nervous system, gastrointestinal and bladder function, fatigue, sexual health, and the musculoskeletal system. 

For some women, the clinical picture is further complicated by chronic overlapping pain conditions. Understanding these connections can help clinicians develop more comprehensive treatment plans and help women advocate for care that addresses their full experience. 

Endometriosis should never be reduced to painful periods. And women should never have to prove how much they are suffering before their symptoms are taken seriously. Every woman deserves an accurate evaluation, access to appropriate treatment, and a healthcare team that sees the whole person—not just one organ, one symptom, or one diagnosis.

References

1. Becker CM, et al. ESHRE guideline: endometriosis. Human Reproduction Open. 2022;2022(2). https://doi.org/10.1093/hropen/hoac009
2. Zondervan KT, Becker CM, Missmer SA. Endometriosis. New England Journal of Medicine. 2020;382:1244–1256. https://doi.org/10.1056/NEJMra1810764
3. Peripheral, Central, and Cross Sensitization in Endometriosis-Associated Pain and Comorbid Pain Syndromes. Frontiers in Reproductive Health. 2021. https://doi.org/10.3389/frph.2021.729642
4. Bartley EJ, Alappattu MJ, Manko K, et al. Presence of endometriosis and chronic overlapping pain conditions negatively impacts the pain experience in women with chronic pelvic–abdominal pain: A cross-sectional survey. Women’s Health. 2024. https://doi.org/10.1177/17455057241248017
5. Till SR, Nakamura R, Schrepf A, As-Sanie S. Approach to diagnosis and management of chronic pelvic pain in women: Incorporating chronic overlapping pain conditions in assessment and management. Obstetrics and Gynecology Clinics of North America. 2022;49(2):219–239. https://doi.org/10.1016/j.ogc.2022.02.006
6. Ramin-Wright A, et al. Fatigue—a symptom in endometriosis. Human Reproduction. 2018;33(8):1459–1465. https://pubmed.ncbi.nlm.nih.gov/29947766/
7. Can G, et al. Physiotherapy for endometriosis-associated pelvic pain: A systematic review and meta-analysis. Pain Medicine. 2026;27(1):95 onward. https://pmc.ncbi.nlm.nih.gov/articles/PMC12773736/

Living with endometriosis and multiple seemingly unrelated symptoms? 

Learn how our Pelvic Overlap Spectrum approach examines the connections among pelvic pain, hypermobility, gastrointestinal symptoms, nervous system function, and whole-body health.