Endometrial polyp Medical Services in China

Endometrial polyps are benign, localized overgrowths of endometrial glands and stroma that project into the uterine cavity. They arise from the functional layer of the endometrium and are typically attached by a stalk (pedunculated) or broad base (sessile). Though histologically benign in >95% of cases, atypical hyperplasia or malignancy—particularly in postmenopausal women or those with risk factors—must be ruled out. Pathogenesis involves dysregulated estrogen stimulation without adequate progesterone opposition, leading to abnormal endometrial proliferation. Localized alterations in sex hormone receptor expression (especially estrogen receptor alpha), angiogenic factors (e.g., VEGF), and inflammatory mediators further promote polyp formation and persistence. Epidemiologically, endometrial polyps affect approximately 10–25% of reproductive-age women and up to 35% of postmenopausal women undergoing evaluation for abnormal uterine bleeding. Prevalence rises with age, obesity, hypertension, and use of tamoxifen. Key modifiable risk factors include chronic anovulation (e.g., PCOS), unopposed estrogen exposure (exogenous or endogenous), obesity (adipose tissue aromatization increases bioavailable estradiol), hypertension, and diabetes mellitus. Non-modifiable risks include advancing age, prior pelvic infection, and history of infertility. Clinically, many polyps are asymptomatic and discovered incidentally during fertility workups or routine ultrasound. Symptomatic presentations include intermenstrual bleeding, menorrhagia, postmenopausal bleeding, and infertility—polyps impair embryo implantation by disrupting endometrial receptivity, altering local cytokine profiles, and causing mechanical interference. Recurrent pregnancy loss is also associated with untreated polyps. Quality of life impact is substantial: chronic bleeding causes fatigue and iron-deficiency anemia; anxiety around cancer risk and fertility uncertainty contributes to psychological distress; sexual discomfort due to spotting may strain relationships; and repeated diagnostic procedures (e.g., saline infusion sonography, hysteroscopy) add physical and emotional burden. In reproductive-aged patients, polyps significantly reduce natural conception rates and IVF success—studies show up to 50% improvement in live birth rates after hysteroscopic polypectomy. Early diagnosis via transvaginal ultrasound (with or without saline infusion) and definitive management through office-based or operative hysteroscopy remain cornerstones of care in reproductive medicine.

Endometrial polyps are benign, localized overgrowths of endometrial glands and stroma that project into the uterine cavity. While their precise pathogenesis remains incompletely elucidated, current evidence points to a multifactorial etiology involving hormonal dysregulation, local tissue-level abnormalities, chronic inflammation, and aberrant angiogenesis. The most well-established cause is unopposed estrogenic stimulation—either endogenous or exogenous—which drives excessive endometrial proliferation without adequate counterbalancing progesterone-mediated differentiation and shedding. This imbalance is commonly observed in anovulatory cycles (e.g., in polycystic ovary syndrome), perimenopause, obesity-related aromatase upregulation, and during tamoxifen therapy. Estrogen receptor alpha (ESR1) overexpression within polyp stroma and glands further amplifies local estrogen sensitivity, contributing to focal hyperplasia.

Triggers for polyp development or growth include cyclic hormonal fluctuations, particularly prolonged estrogen exposure during extended follicular phases or luteal phase deficiency; iatrogenic factors such as long-term use of selective estrogen receptor modulators (e.g., tamoxifen, which acts as an estrogen agonist in endometrial tissue); and postmenopausal hormone therapy lacking adequate progestogen opposition. Acute or chronic intrauterine inflammation—often associated with prior instrumentation (e.g., dilation and curettage, hysteroscopic procedures), chronic endometritis, or subclinical infection—may induce cytokine-mediated stromal remodeling and vascular endothelial growth factor (VEGF) upregulation, fostering polyp initiation and neovascularization.

Key modifiable risk factors include obesity (BMI ≥30 kg/m²), which increases peripheral aromatization of androgens to estradiol in adipose tissue and elevates bioavailable estrogen levels; hypertension and metabolic syndrome, likely through shared inflammatory and endothelial dysfunction pathways; and nulliparity, possibly reflecting cumulative lifetime estrogen exposure without the protective effect of pregnancy-associated progesterone surges and endometrial quiescence. Age is a strong non-modifiable risk factor: prevalence rises significantly after age 40, peaks in the perimenopausal decade (45–55 years), and remains elevated in early postmenopause—though polyps may occur at any reproductive age, including adolescence in rare cases of endocrine disorders.

Genetic factors play a contributory role, though endometrial polyps are not classically hereditary. Somatic mutations—including recurrent KRAS exon 2 mutations (codon 12/13), PIK3CA hotspot mutations (exons 9 and 20), and less frequently ARID1A loss—are frequently detected in polyp epithelium and stroma, suggesting clonal expansion driven by oncogenic signaling pathways regulating cell proliferation and survival. Germline variants in genes involved in estrogen metabolism (e.g., CYP19A1, COMT) or DNA repair (e.g., BRCA1/2 carriers show modestly increased prevalence, though not causally linked) may confer subtle susceptibility. Notably, Lynch syndrome (hereditary nonpolyposis colorectal cancer) is not associated with increased polyp incidence, distinguishing it from endometrial carcinoma risk.

Environmental and lifestyle exposures also contribute. Chronic low-grade systemic inflammation induced by poor diet, sedentary behavior, or smoking may exacerbate endometrial immune dysregulation and oxidative stress, promoting stromal fibroblast activation and extracellular matrix deposition. Exposure to endocrine-disrupting chemicals (EDCs)—such as bisphenol A (BPA), phthalates, and certain pesticides—has been implicated in vitro and in epidemiologic studies for altering estrogen receptor signaling, disrupting steroidogenesis, and inducing epigenetic modifications (e.g., promoter methylation of tumor suppressor genes like PTEN) in endometrial cells. Additionally, long-term use of intrauterine devices (IUDs), particularly levonorgestrel-releasing systems, appears protective due to local progestogenic effects, whereas copper IUDs show neutral or slightly increased association in some cohorts—potentially related to chronic foreign-body inflammation. Finally, socioeconomic determinants—including limited access to gynecologic care, delayed diagnosis of menstrual disorders, and disparities in obesity management—indirectly influence polyp detection, symptom burden, and complication rates (e.g., infertility, abnormal uterine bleeding, or progression to atypical hyperplasia in rare cases). Collectively, endometrial polyp formation reflects an interplay of endocrine, genetic, inflammatory, and environmental forces converging on the endometrial microenvironment.

Endometrial polyps are benign, localized overgrowths of endometrial glands and stroma, often pedunculated or sessile, arising from the uterine cavity. They are common in reproductive-aged and perimenopausal women, with prevalence increasing with age, obesity, hypertension, and use of tamoxifen. While many polyps are asymptomatic—detected incidentally during imaging or hysteroscopy for unrelated indications—their clinical presentation varies significantly depending on size, number, location, vascularization, and hormonal milieu.

Early symptoms are frequently subtle and nonspecific. In premenopausal women, the earliest manifestation may be mild intermenstrual spotting—light, self-limited bleeding occurring between regular menses—often dismissed as stress-related or cycle irregularity. Some patients report a change in menstrual flow pattern, such as prolonged follicular-phase spotting or increased variability in cycle length (e.g., oligomenorrhea alternating with polymenorrhea), preceding overt abnormal uterine bleeding (AUB). In perimenopausal women, early signs may include resumption or recurrence of vaginal bleeding after a period of amenorrhea lasting ≥6 months—a red-flag symptom warranting prompt evaluation. Asymptomatic polyps may also present initially with infertility, particularly when located near the tubal ostia or fundus, where they may mechanically impede sperm transport, embryo implantation, or disrupt local endometrial receptivity via altered cytokine expression and chronic low-grade inflammation.

Typical symptoms center around abnormal uterine bleeding (AUB), classified per the PALM-COEIN system as AUB-P (polyp-related). The most characteristic presentation is menometrorrhagia: heavy, prolonged, and irregular bleeding that may occur throughout the cycle. Menorrhagia (excessive menstrual blood loss >80 mL/cycle or duration >7 days) is common, often accompanied by passage of clots. Postcoital bleeding—bright red, non-painful spotting following intercourse—is highly suggestive of a cervical or lower uterine segment polyp but may also occur with fundal or mid-cavity polyps if friable or ulcerated. Postmenopausal vaginal bleeding (PMVB), defined as any vaginal bleeding occurring ≥12 months after final menses, is the single most concerning and frequent symptomatic presentation; up to 85% of women presenting with PMVB are found to have endometrial pathology, with polyps accounting for ~30–40% of benign causes. Notably, while most endometrial polyps are benign, PMVB mandates exclusion of endometrial hyperplasia or carcinoma, especially in women with risk factors (e.g., unopposed estrogen exposure, diabetes, Lynch syndrome).

Accompanying symptoms are generally absent but may include pelvic pressure or dull, noncyclic lower abdominal discomfort in cases of large (>2 cm), multiple, or pedunculated polyps that undergo torsion or prolapse through the external os. Vaginal discharge—typically watery, serosanguineous, or mucoid—may occur, particularly with larger or infected polyps. Dyspareunia is uncommon but possible with prolapsed or ulcerated lesions. Infertility remains a critical accompanying feature: meta-analyses indicate that endometrial polyps reduce spontaneous pregnancy rates by ~35% and decrease live birth rates in both natural conception and assisted reproductive technology (ART) cycles. Recurrent implantation failure (RIF) in IVF patients is strongly associated with polyp presence, even when asymptomatic.

Complications arise primarily from chronic hemorrhage, mechanical disruption, or malignant transformation. Iron-deficiency anemia may develop secondary to prolonged or heavy AUB, manifesting as fatigue, pallor, tachycardia, or exertional dyspnea. Polyp prolapse into the endocervix or vagina can cause persistent irritation, secondary infection, necrosis, or ulceration—leading to foul-smelling discharge or acute pain. Rarely, large pedunculated polyps undergo torsion, resulting in acute, colicky pelvic pain and potential infarction. Although malignancy is rare (<5% overall, <1% in premenopausal women), risk escalates with age, postmenopausal status, polyp size >1.5 cm, and comorbidities such as obesity or tamoxifen use. Atypical hyperplasia or adenocarcinoma may arise within polyps, necessitating histopathologic confirmation in all excised specimens. Additionally, polyps contribute to recurrent miscarriage, likely via impaired decidualization, aberrant angiogenesis, or local immune dysregulation.

Diagnosis relies on a multimodal approach. Transvaginal ultrasound (TVUS) is first-line: polyps appear as well-defined, homogeneous, echogenic or hypoechoic intracavitary masses, often with a surrounding hypoechoic halo and central vessels visible on Doppler. Saline infusion sonohysterography (SIS) significantly improves sensitivity (95–98%) and specificity (85–90%) by distending the cavity and delineating polyp morphology, vascularity, and attachment site. Hysteroscopy remains the gold standard for definitive diagnosis and concurrent treatment; it allows direct visualization, assessment of number/size/location, and targeted biopsy or resection. Endometrial biopsy (pipelle) has limited utility for polyp detection—sensitivity ranges from 30–50%—and is not recommended as a primary is reserved for complex cases (e.g., suspected malignancy, deep myometrial invasion, or differential from submucosal fibroids) and demonstrates intermediate signal intensity on T2-weighted images with characteristic 'stalk' enhancement.

Differential diagnosis includes several entities presenting with AUB or infertility. Submucosal leiomyomas typically demonstrate a hypointense rim on T2 MRI and may show more pronounced mass effect or distortion of the endometrial stripe on TVUS/SIS. Endometrial hyperplasia presents with diffuse endometrial thickening rather than discrete focal lesions; however, atypical hyperplasia may coexist with polyps. Endometrial carcinoma usually manifests as heterogeneous, irregular, or polypoid endometrial thickening with abnormal vascularity and may invade the myometrium—features best assessed via MRI or diagnostic hysteroscopy with directed biopsy. Endometritis may mimic polyps on imaging with focal echogenicity but is associated with clinical signs of infection (fever, purulent discharge) and elevated inflammatory markers. Cervical polyps are distinguished by their origin at the external os and typically lack association with AUB beyond postcoital spotting. Finally, endometrial intraepithelial neoplasia (EIN) or early adenocarcinoma may present as a subtle focal lesion indistinguishable from a benign polyp without histology—underscoring the necessity of pathologic evaluation of all resected tissue. Accurate differentiation hinges on integrating clinical history, imaging characteristics, hysteroscopic appearance, and mandatory histopathologic analysis.

Endometrial polyps are benign, localized overgrowths of endometrial glands and stroma that project into the uterine cavity. They are common in reproductive-aged and perimenopausal women, with prevalence estimates ranging from 10% to 30% in asymptomatic populations and up to 45% in women presenting with abnormal uterine bleeding (AUB), infertility, or recurrent pregnancy loss. In the Department of Reproductive Medicine, management is individualized based on symptomatology, reproductive goals, polyp size and number, patient age, comorbidities, and risk for malignancy—particularly in postmenopausal women or those with risk factors such as obesity, unopposed estrogen exposure, or Lynch syndrome.

Conservative management is appropriate for asymptomatic, small (<1.5 cm), solitary polyps in premenopausal women without fertility concerns or risk factors for endometrial neoplasia. Serial surveillance via transvaginal ultrasound (TVUS) every 6–12 months may be considered, especially when polyps are incidentally detected. However, spontaneous regression occurs in only 2.7–12% of cases, and persistent polyps—even if asymptomatic—may impair endometrial receptivity and reduce implantation rates in assisted reproductive technology (ART) cycles. Therefore, conservative observation is rarely recommended for patients undergoing fertility evaluation or treatment.

Pharmacologic therapy has limited efficacy for definitive polyp resolution but plays a supportive role. Progestins—including oral micronized progesterone (200 mg daily for 10–14 days per cycle), medroxyprogesterone acetate (10 mg daily for 10–14 days), or levonorgestrel-releasing intrauterine systems (LNG-IUS)—may suppress polyp growth and alleviate AUB by counteracting estrogen-driven proliferation. While LNG-IUS demonstrates high efficacy in controlling menorrhagia and reducing polyp recurrence post-hysteroscopy (RR 0.38; 95% CI 0.21–0.69), it does not reliably eliminate existing polyps. Selective progesterone receptor modulators (SPRMs) like ulipristal acetate have shown transient reduction in polyp volume in small trials but are not approved for this indication and carry safety concerns regarding liver toxicity. Gonadotropin-releasing hormone agonists (GnRHa) are occasionally used preoperatively to shrink large or vascular polyps, particularly in cases of severe anemia or anticipated surgical complexity, though evidence remains limited and their use is off-label for polyp management.

Surgical hysteroscopic polypectomy remains the gold-standard treatment, especially for symptomatic polyps, infertility-related indications, or polyps >1.5 cm. Performed under direct visualization using either rigid or flexible hysteroscopes, the procedure involves mechanical resection with cold-loop or bipolar electrosurgical instruments. In reproductive medicine settings, emphasis is placed on preserving endometrial integrity: sharp dissection with micro-instruments or low-power bipolar energy minimizes thermal injury to the underlying basalis layer, thereby safeguarding future endometrial regeneration and receptivity. Outpatient hysteroscopy under local anesthesia (e.g., paracervical block + intracervical lidocaine) is increasingly standard, with success rates exceeding 95% and complication rates <1% (including uterine perforation, fluid overload, or infection). For complex cases—such as multiple, broad-based, or recurrent polyps—operative hysteroscopy in an operating room under general or spinal anesthesia is preferred. Histopathologic examination of all resected specimens is mandatory to exclude atypical hyperplasia or endometrial carcinoma, particularly in high-risk cohorts.

Treatment in China offers distinct advantages within reproductive medicine practice. First, China’s national standardization of hysteroscopic training—mandated by the National Health Commission—ensures widespread access to high-fidelity simulation-based certification and continuous competency assessment for gynecologists. Second, advanced hysteroscopic platforms (e.g., Karl Storz, Olympus, and domestic leaders like Wisonic and Urologix) are widely deployed across tier-1 to tier-3 hospitals, enabling real-time digital imaging, image enhancement (NBI, ICG), and integrated morcellation systems that improve precision and reduce operative time. Third, China’s robust ART infrastructure facilitates seamless integration of polypectomy into fertility pathways: same-cycle embryo transfer is routinely offered following hysteroscopic resection in select patients with favorable endometrial morphology, supported by Level I evidence from multicenter RCTs conducted in Beijing, Shanghai, and Guangzhou. Fourth, cost-effectiveness is notable—outpatient hysteroscopy costs approximately USD $300–$600, significantly lower than comparable procedures in Western countries, without compromising quality or safety metrics. Finally, China’s centralized electronic health record system enables longitudinal tracking of polyp recurrence, fertility outcomes, and long-term endometrial health, contributing to nationally aggregated outcome databases that inform evidence-based guidelines.

Post-procedural recovery emphasizes rapid return to normal activity while minimizing complications. Patients are advised to avoid sexual intercourse, tampon use, and immersion baths for 10–14 days to reduce infection risk. Mild cramping and light spotting for 3–7 days are expected; NSAIDs (e.g., ibuprofen 400 mg TID PRN) are first-line for analgesia. Hormonal suppression—typically with cyclic oral progestins or LNG-IUS—is initiated within 1–2 weeks post-polypectomy to inhibit recurrence, which affects 2.5–43% of patients within 12 months depending on baseline risk. For fertility patients, ovulation induction or timed intercourse may resume in the subsequent cycle if endometrial healing is confirmed via saline-infusion sonohysterography (SIS) or office hysteroscopy. Nutritional counseling focuses on anti-inflammatory dietary patterns (rich in omega-3 fatty acids, fiber, and antioxidants) and weight optimization in overweight patients, given the strong association between BMI >25 kg/m² and polyp recurrence. Follow-up includes TVUS at 3 months to assess for recurrence and, in infertility cases, endometrial receptivity testing (ERA) or chronic endometritis screening (CD138 immunohistochemistry) if implantation failure persists. Long-term surveillance is recommended for high-risk individuals, including annual endometrial sampling or hysteroscopy every 2–3 years in postmenopausal women with prior polyps.