Endometriosis Medical Services in China

Endometriosis is a chronic, estrogen-dependent gynecological disorder characterized by the presence of endometrial-like tissue—glands and stroma—outside the uterine cavity. This ectopic tissue most commonly implants on the ovaries, fallopian tubes, pelvic peritoneum, uterosacral ligaments, and rectovaginal septum; less frequently, it may involve distant sites such as the lungs, diaphragm, or abdominal scars. The disease is associated with inflammation, fibrosis, adhesion formation, and cyclic bleeding—leading to progressive pelvic pain, infertility, and organ dysfunction. Pathogenesis remains incompletely understood but involves multiple interrelated mechanisms: retrograde menstruation (with impaired immune clearance), coelomic metaplasia, lymphatic/vascular dissemination, stem cell recruitment, and genetic-epigenetic dysregulation. Recent evidence highlights aberrant neuroangiogenesis, macrophage polarization defects, and progesterone resistance as key contributors to lesion survival and symptom persistence. Epidemiologically, endometriosis affects approximately 6–10% of reproductive-age women globally—translating to over 190 million individuals. Among women with chronic pelvic pain, prevalence rises to 30–50%; among those with infertility, it reaches 25–50%. Risk factors include early menarche, short menstrual cycles (<27 days), heavy or prolonged menses, nulliparity, low body mass index (BMI), family history (first-degree relatives increase risk 7-fold), and certain genetic variants (e.g., SNPs in WNT4, GREB1, FN1). Protective factors include multiparity, late menarche, and long-term combined oral contraceptive use. Endometriosis profoundly impairs quality of life: 70–90% of affected women report moderate-to-severe dysmenorrhea, 50–70% experience deep dyspareunia, and 30–40% suffer chronic non-cyclical pelvic pain. Fatigue, gastrointestinal symptoms (bloating, diarrhea, constipation—often misdiagnosed as IBS), urinary urgency, and depression/anxiety are highly prevalent. Up to 40% report work absenteeism or reduced productivity; many delay diagnosis by 6–10 years due to normalization of pain and fragmented care pathways. The condition also correlates with increased risks of autoimmune disorders (e.g., SLE, Hashimoto’s thyroiditis), ovarian cancer (particularly clear-cell and endometrioid subtypes), and cardiovascular morbidity later in life. Early recognition, multidisciplinary management—including reproductive endocrinology, pain medicine, colorectal surgery, and urology—is essential to mitigate long-term sequelae and preserve fertility.

Endometriosis is a chronic, estrogen-dependent inflammatory disorder characterized by the presence of endometrial-like tissue (glands and stroma) outside the uterine cavity—most commonly on the ovaries, pelvic peritoneum, uterosacral ligaments, and rectovaginal septum. While its precise etiology remains incompletely elucidated, current evidence supports a multifactorial pathogenesis involving retrograde menstruation, coelomic metaplasia, lymphovascular dissemination, stem cell recruitment, and immune dysregulation. Retrograde menstruation—the reflux of menstrual effluent containing viable endometrial cells through patent fallopian tubes into the peritoneal cavity—is considered the most widely accepted initiating event; however, it occurs in up to 90% of menstruating individuals without resulting in endometriosis, underscoring the necessity of concomitant peritoneal immune tolerance failure. In affected individuals, impaired natural killer (NK) cell cytotoxicity, aberrant macrophage polarization (toward M2 anti-inflammatory phenotype), and defective clearance of ectopic endometrial cells permit their adhesion, invasion, angiogenesis, and neurogenesis within the pelvic microenvironment. Genetic factors play a substantial role: genome-wide association studies (GWAS) have identified over 40 risk loci, including variants in genes involved in sex steroid signaling (e.g., ESR1, GREB1), inflammation (IL1A, TNF), and developmental pathways (WNT4, VEZT). First-degree relatives of individuals with endometriosis exhibit a 6- to 10-fold increased risk, and heritability estimates range from 50% to 75%. Epigenetic modifications—including global DNA hypomethylation, hypermethylation of HOXA10 and progesterone receptor (PGR) promoters, and dysregulated microRNA expression (e.g., miR-196b, miR-125b)—further contribute to progesterone resistance and estrogen dominance. Environmental exposures are increasingly implicated as modulators of disease susceptibility and progression. Dioxins (e.g., TCDD) and polychlorinated biphenyls (PCBs) act as aryl hydrocarbon receptor (AhR) agonists, disrupting estrogen metabolism, promoting oxidative stress, and enhancing proinflammatory cytokine production. Endocrine-disrupting chemicals (EDCs) such as bisphenol A (BPA) and phthalates interfere with nuclear hormone receptor function, alter steroidogenesis, and impair decidualization. Early-life exposures—including prenatal diethylstilbestrol (DES) exposure and childhood obesity—may program long-term reproductive tract immunity and hormonal homeostasis. Clinical triggers include prolonged unopposed estrogen exposure (e.g., early menarche, late menopause, anovulatory cycles), nulliparity, and short menstrual cycles (<27 days) with heavy or prolonged flow—each increasing cumulative retrograde flux and endometrial cell burden. Conversely, multiparity, lactation, and oral contraceptive use are associated with reduced incidence, likely via suppression of ovulation and endometrial proliferation. Additional risk factors encompass Müllerian anomalies (e.g., obstructive uterine malformations causing outflow obstruction), pelvic surgeries (e.g., cesarean delivery or hysterectomy with retained endometrial tissue), and autoimmune comorbidities (e.g., systemic lupus erythematosus, Sjögren syndrome), suggesting shared immunogenetic underpinnings. Notably, socioeconomic and diagnostic delays—particularly among marginalized populations—contribute to prolonged symptom duration and advanced-stage disease at diagnosis, though these reflect healthcare inequities rather than biological causation. Importantly, endometriosis is not caused by lifestyle choices, poor hygiene, or sexual activity. Emerging research highlights the role of gut and endometrial microbiota dysbiosis in modulating local inflammation and barrier integrity, while mitochondrial dysfunction and metabolic reprogramming in ectopic lesions support their survival in hostile microenvironments. Understanding this complex interplay of genetic predisposition, epigenetic reprogramming, environmental insult, and immune-endocrine crosstalk is essential for developing targeted diagnostics and therapeutics in reproductive medicine.

Endometriosis is a chronic, estrogen-dependent, inflammatory gynecologic disorder characterized by the presence of endometrial-like glandular and stromal tissue outside the uterine cavity. It predominantly affects individuals of reproductive age (15–49 years), with an estimated prevalence of 6–10% among this population. While its pathogenesis remains incompletely understood, retrograde menstruation, coelomic metaplasia, lymphatic/vascular dissemination, and stem cell-mediated implantation are leading hypotheses. Clinical presentation is highly heterogeneous—ranging from asymptomatic cases detected incidentally during fertility evaluation or surgery to debilitating pain and infertility—making early recognition critical for timely intervention.

Early symptoms often manifest in adolescence or early adulthood and may be dismissed as 'normal' menstrual discomfort. The most common early sign is dysmenorrhea—progressively worsening, midline, crampy lower abdominal or pelvic pain beginning 1–2 days before menses and peaking on days 1–2. Unlike primary dysmenorrhea, endometriosis-associated dysmenorrhea typically fails to respond adequately to NSAIDs or combined hormonal contraceptives and may intensify over successive cycles. Other early indicators include chronic noncyclic pelvic pain (present >50% of days over ≥6 months), dyspareunia—particularly deep, posterior, or thrust-related pain—and cyclical gastrointestinal symptoms such as bloating, constipation, or diarrhea that worsen premenstrually or during menses. Adolescents may present with severe school absenteeism, reduced physical activity, or avoidance of sports due to pain; notably, up to 70% of adolescents with chronic pelvic pain meeting criteria for endometriosis have normal pelvic ultrasound findings, underscoring the limitations of imaging in early disease.

Typical symptoms reflect lesion location and inflammatory burden. Pelvic pain remains the cardinal feature: it is often described as deep, aching, or stabbing, localized to the lower abdomen, sacrum, or posterior pelvis, and may radiate to the thighs or lower back. Dyspareunia is reported by 70–90% of affected individuals and correlates strongly with posterior cul-de-sac, uterosacral ligament, or rectovaginal septum involvement. Dyschezia—painful defecation, especially during menses—is highly suggestive of rectosigmoid or rectovaginal endometriosis. Cyclical urinary symptoms—including dysuria, frequency, urgency, or hematuria—may occur with bladder or ureteral involvement. Fatigue, low-grade fever, and generalized malaise are frequently underrecognized systemic manifestations linked to chronic inflammation and cytokine dysregulation (e.g., elevated IL-6, TNF-α).

Accompanying symptoms extend beyond the pelvis. Endometriosis is associated with comorbid functional disorders: irritable bowel syndrome (IBS)-like symptoms (bloating, alternating constipation/diarrhea) occur in ~35–50% of patients, while interstitial cystitis/painful bladder syndrome overlaps in ~10–20%. Mood disturbances—including anxiety (prevalence ~45%), depression (30–40%), and somatization—are prevalent and bidirectionally linked to chronic pain and quality-of-life impairment. Sleep disruption, cognitive fog ('endofog'), and reduced work productivity are common. Notably, up to 30–50% of individuals with endometriosis meet diagnostic criteria for central sensitization, contributing to widespread hyperalgesia and allodynia.

Complications arise from progressive fibrosis, adhesion formation, and organ infiltration. Infertility affects 30–50% of individuals with endometriosis and results from multiple mechanisms: distorted pelvic anatomy, impaired oocyte quality, altered folliculogenesis, luteal phase defects, and peritoneal inflammation compromising sperm function and embryo implantation. Ovarian endometriomas (>3 cm) increase oxidative stress and reduce ovarian reserve (AMH decline). Deep infiltrating endometriosis (DIE) involving the uterosacral ligaments, rectovaginal septum, or bowel may cause ureteral obstruction (leading to hydronephrosis and renal impairment), bowel stenosis, or rectovaginal fistulae—though rare, these represent surgical emergencies. Chronic pain can lead to opioid dependence, deconditioning, and iatrogenic complications from repeated interventions.

Diagnosis remains challenging due to symptom overlap and lack of noninvasive biomarkers. Clinical suspicion based on history is paramount. Transvaginal ultrasound (TVUS) performed by an expert sonographer is first-line imaging: it reliably detects ovarian endometriomas (ground-glass echogenicity, avascular cysts), DIE nodules (hypoechoic, irregular, often with shadowing), and adenomyosis. MRI offers superior soft-tissue contrast for mapping deep lesions, particularly in the bowel, bladder, or sciatic nerve region, but lacks specificity without correlation. Serum CA-125 may be modestly elevated in moderate-to-severe disease but lacks sensitivity for early-stage or minimal disease and is not diagnostic. Definitive diagnosis requires laparoscopic visualization with histopathologic confirmation: typical lesions appear as blue-black 'powder-burn' implants, red flame-like active foci, white scarring, or yellow-brown peritoneal discoloration. Biopsy is recommended for atypical or nonpigmented lesions to exclude malignancy.

Differential diagnosis must exclude conditions mimicking endometriosis clinically and radiologically. Primary dysmenorrhea presents with similar cyclical pain but lacks progression, deep dyspareunia, or infertility and responds well to NSAIDs/hormonal therapy. Adenomyosis causes heavy menstrual bleeding (menorrhagia), uterine enlargement, and clots but typically spares deep dyspareunia unless coexistent. Pelvic inflammatory disease (PID) features acute febrile illness, cervical motion tenderness, and purulent discharge—though chronic PID may mimic endometriosis. IBS and inflammatory bowel disease (IBD) share GI symptoms but lack cyclical exacerbation and pelvic findings. Ovarian torsion or appendicitis present acutely with peritoneal signs. Malignancies—including ovarian carcinoma or primary peritoneal cancer—may present with ascites, nodularity, or rapid progression; CA-125 elevation is more pronounced and often accompanied by imaging red flags (e.g., solid components, papillary projections). Finally, musculoskeletal causes (e.g., piriformis syndrome, sacroiliac joint dysfunction) and neuropathic pain (e.g., pudendal neuralgia) require careful neurologic and orthopedic assessment to avoid misattribution.

Endometriosis is a chronic, estrogen-dependent inflammatory disorder characterized by the presence of endometrial-like tissue outside the uterine cavity—commonly involving the ovaries, pelvic peritoneum, uterosacral ligaments, and rectovaginal septum. It affects approximately 10% of reproductive-age women globally and is strongly associated with pelvic pain, dysmenorrhea, dyspareunia, infertility, and reduced quality of life. Management in the Department of Reproductive Medicine is individualized, multidisciplinary, and guided by symptom severity, disease extent (per ASRM staging), fertility goals, patient age, and prior treatment response.

Conservative treatment forms the cornerstone of initial management, particularly for mild-to-moderate symptoms or when fertility preservation is paramount. This includes lifestyle modifications, physical therapy, and non-pharmacologic interventions. Pelvic floor physical therapy—delivered by certified specialists—addresses myofascial trigger points, hypertonicity, and neuromuscular dysfunction contributing to chronic pelvic pain. Dietary strategies emphasizing anti-inflammatory foods (e.g., omega-3 fatty acids, fiber-rich vegetables, low-glycemic-index carbohydrates) and avoidance of processed foods, excess alcohol, and trans fats may modestly reduce systemic inflammation and oxidative stress. Regular aerobic exercise (≥150 minutes/week) improves endorphin release, reduces estrogen bioavailability via adipose tissue modulation, and enhances autonomic regulation. Cognitive behavioral therapy (CBT) and mindfulness-based stress reduction are evidence-supported adjuncts for pain coping, emotional resilience, and functional restoration—particularly valuable given the high comorbidity with anxiety, depression, and central sensitization.

Pharmacologic therapy targets hormonal suppression, inflammation, and pain pathways. First-line agents include combined oral contraceptives (COCs), administered continuously (i.e., skipping placebo weeks) to suppress ovulation and decidualize ectopic implants. Progestin-only options—such as norethindrone acetate, dienogest, or the levonorgestrel-releasing intrauterine system (LNG-IUS)—are preferred in patients contraindicated for estrogen (e.g., migraine with aura, thrombophilia history). Dienogest, approved specifically for endometriosis in multiple jurisdictions including China, demonstrates potent anti-proliferative and anti-angiogenic effects on lesions with favorable tolerability. Gonadotropin-releasing hormone (GnRH) agonists (e.g., leuprolide) induce hypoestrogenic amenorrhea but require add-back therapy (e.g., low-dose estradiol/norethindrone) after 6 months to mitigate bone mineral density loss and vasomotor symptoms. GnRH antagonists (e.g., elagolix, relugolix) offer rapid, dose-titratable suppression with improved safety profiles and are increasingly utilized in refractory cases. Nonsteroidal anti-inflammatory drugs (NSAIDs) provide symptomatic relief but lack disease-modifying effects; they are best used short-term and at lowest effective dose due to gastrointestinal and renal risks. Emerging agents—including aromatase inhibitors (e.g., letrozole) in combination with ovarian suppression—and selective progesterone receptor modulators (SPRMs) are under active investigation in clinical trials, especially for deep infiltrating endometriosis (DIE) and recurrent disease.

Surgical intervention is indicated for severe pain unresponsive to medical therapy, large endometriomas (>4 cm), suspected bowel or ureteral involvement, or infertility evaluation/treatment. Laparoscopy remains the gold standard: diagnostic confirmation requires histopathologic verification, while excisional surgery—performed by advanced laparoscopic surgeons trained in deep infiltrating endometriosis—is superior to ablation for long-term pain reduction and fertility outcomes. Complete excision of all visible lesions—including retrocervical, uterosacral, and rectovaginal nodules—minimizes recurrence risk. In cases of ovarian endometriomas, cystectomy with meticulous stripping technique preserves ovarian reserve better than coagulation or drainage alone. For DIE involving bowel or bladder, multidisciplinary collaboration with colorectal or urologic surgeons ensures safe resection and reconstruction. Hysterectomy with bilateral salpingo-oophorectomy is reserved for definitive management in patients who have completed childbearing and suffer debilitating symptoms refractory to all other modalities; however, even then, residual extrauterine disease may persist if not fully excised.

Treatment in China offers distinct advantages within the Reproductive Medicine framework. First, China’s national endometriosis referral network integrates tertiary reproductive centers with standardized surgical training programs—many led by surgeons certified by the Chinese Medical Association’s Endometriosis Task Force—ensuring high-volume expertise in complex excision. Second, domestic pharmaceutical innovation has accelerated access: dienogest and relugolix are widely available and reimbursed under the National Reimbursement Drug List (NRDL), reducing out-of-pocket burden. Third, integrative approaches are systematically incorporated: acupuncture—validated in RCTs for pain reduction and menstrual regulation—is routinely offered alongside conventional care in major centers such as Peking University Third Hospital and Shanghai Jiao Tong University Affiliated International Peace Maternity and Child Health Hospital. Fourth, China’s robust assisted reproductive technology (ART) infrastructure enables seamless transition from surgical management to IVF/ICSI when fertility is compromised, with cumulative live birth rates exceeding 60% per initiated cycle in endometriosis-related infertility managed at top-tier centers.

Post-treatment recovery emphasizes continuity and prevention. Patients undergoing surgery should avoid heavy lifting (>5 kg), sexual intercourse, and swimming for 4–6 weeks to allow peritoneal healing. Hormonal maintenance therapy—typically COCs or progestins—is strongly recommended postoperatively to delay recurrence; studies show a 50–70% reduction in 5-year recurrence with continuous suppression. Fertility counseling must be timely: for those desiring conception, spontaneous conception is encouraged within 6–12 months post-excision; beyond that, expedited ART referral is advised. Bone health monitoring (DEXA scan) is warranted for patients on prolonged GnRH analogues. Annual gynecologic evaluation—including transvaginal ultrasound with bowel preparation when indicated—facilitates early detection of recurrence. Psychological support remains integral: dedicated endometriosis nurse coordinators in leading Chinese hospitals provide longitudinal education, symptom tracking tools, and peer-support group linkages. Ultimately, optimal management hinges on shared decision-making, realistic expectation-setting, and lifelong partnership between patient and reproductive medicine specialist.