Endometriosis · Pathophysiology
Orr NL, Albert A, Liu YD, Lum A, Hong J, Ionescu CL, Senz J, Nazeran TM, Lee AF, Noga H, Lawrenson K, Allaire C, Williams C, Bedaiwy MA, Anglesio MS, Yong PJ
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The clinical phenotype of somatic mutations in endometriosis is unknown. The objective was to determine whether somatic KRAS mutations were associated with greater disease burden in endometriosis (i.e. more severe subtypes and higher stage). This prospective longitudinal cohort study included 122 subjects undergoing endometriosis surgery at a tertiary referral center between 2013 and 2017, with 5-9 years of follow-up. Somatic activating KRAS codon 12 mutations were detected in endometriosis lesions using droplet digital PCR. KRAS mutation status for each subject was coded as present (KRAS mutation in at least one endometriosis sample in a subject) or absent. Standardized clinical phenotyping for each subject was carried out via linkage to a prospective registry. Primary outcome was anatomic disease burden, based on distribution of subtypes (deep infiltrating endometriosis, ovarian endometrioma, and superficial peritoneal endometriosis) and surgical staging (Stages I-IV). Secondary outcomes were markers of surgical difficulty, demographics, pain scores, and risk of re-operation. KRAS mutation presence was higher in subjects with deep infiltrating endometriosis or endometrioma lesions only (57.9%; 11/19) and subjects with mixed subtypes (60.6%; 40/66), compared with those with superficial endometriosis only (35.1%; 13/37) (p = 0.04). KRAS mutation was present in 27.6% (8/29) of Stage I cases, in comparison to 65.0% (13/20) of Stage II, 63.0% (17/27) of Stage III, and 58.1% (25/43) of Stage IV cases (p = 0.02). KRAS mutation was also associated with greater surgical difficulty (ureterolysis) (relative risk [RR] = 1.47, 95% CI: 1.02-2.11) and non-Caucasian ethnicity (RR = 0.64, 95% CI: 0.47-0.89). Pain severities did not differ based on KRAS mutation status, at either baseline or follow-up. Re-operation rates were low overall, occurring in 17.2% with KRAS mutation compared with 10.3% without (RR = 1.66, 95% CI: 0.66-4.21). In conclusion, KRAS mutations were associated with greater anatomic severity of endometriosis, resulting in increased surgical difficulty. Somatic cancer-driver mutations may inform a future molecular classification of endometriosis.
Rojas HE et al., 2026 · Journal of women's health (2002)
To characterize differences between individuals with and without mid-cycle pain in a registry cohort with endometriosis. Prospective analysis of data from the Endometriosis Pelvic Pain Interdisciplinary Cohort Data Registry (Clinicaltrials.gov #NCT02911090) at a tertiary referral center in Western Canada. Three hundred forty-five individuals aged 18-49 years who: (1) had at least one episode of menstrual bleeding in the last 3 months, (2) attended a baseline initial visit, and (3) subsequently had surgery with histological confirmation of endometriosis between January 2018 and December 2023. Exclusion criteria included (1) previous hysterectomy; (2) hormonal suppressive therapy use in the last 3 months; and (3) missing data on mid-cycle pain, history of hormonal therapy use, or menstrual cycle regularity. N/A. Mid-cycle pain in the last month versus No mid-cycle pain in the last month. Of the 345 participants, 67% (n = 232) reported mid-cycle pain in the last month. Mid-cycle pain in the last month was significantly associated with higher mean Central Sensitization Inventory score (48 ± 17 versus 36 ± 16, p < 0.001) and more months of prior hormonal suppressive therapy use (58 [14-120] versus 26 [0-109], p = 0.012). Abnormal anatomy at the time of surgery (e.g., endometrioma, ovarian adhesions) was not associated with mid-cycle pain in the last month. In this endometriosis cohort at a tertiary referral center, most participants reported mid-cycle pain in the last month, which was associated with central sensitization but was not clearly related to endometriosis anatomical distortion.
Balachandran S et al., 2026 · Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC
To assess the impact of the COVID-19 pandemic on reproductive outcomes in patients with recurrent pregnancy loss (RPL) and the influence of material and social deprivation on these outcomes. This retrospective cohort study included RPL patients seen at a specialized clinic between March 1, 2018, and February 28, 2022. Patients were categorized into two groups based on care period: pre-pandemic (March 1, 2018-February 29, 2020) and pandemic (March 1, 2020-February 28, 2022). Cumulative probabilities of birth were estimated using the cumulative incidence function within a competing risk framework, treating pregnancy loss as a competing event. Fine and Gray regression models calculated sub-distribution hazard ratio (sHR) of birth. 544 patients were included in the study, with 255 in the pre-pandemic group and 289 in the pandemic group. Individuals in the pandemic group were less likely to achieve pregnancy than those in the pre-pandemic group (relative risk = 0.50, 95% confidence interval [CI] 0.39 - 0.66). Among those who conceived, the cumulative probability of live birth was 0.77 in both groups. Relative to individuals residing in high-social deprivation neighborhoods, those living in moderately deprived areas had higher sub-distribution hazards of live birth (adjusted sHR = 1.97, 95% CI 1.25 - 3.10; P = 0.003). Within specialized RPL care and a universal maternity care system, pregnancy rates were lower during the first two years of the COVID-19 pandemic. However, among those who conceived, the probability of achieving a live birth remained similar between the pre-pandemic and pandemic periods.
Bouchard TP et al., 2026 · Reproductive biomedicine online · Free to read
Does formation of the corpus luteum help to identify the day of ovulation on ultrasound when follicular collapse is missed, and how reliable are sonographers versus a review panel in identifying the day of ovulation on ultrasound? Sonographers in a clinic in Canada performed serial endovaginal ultrasound scans (six to eight per cycle) to identify the day of ovulation in regularly cycling women (n = 40) who were followed for one to five cycles (n = 85). The day of ovulation was identified by: (i) identification of the dominant follicle; (ii) disappearance of the dominant follicle; and (iii) identification and dating of the corpus luteum. The main outcome measures were inter-rater reliability between two sonographers, and Bland-Altman agreement between the supervising sonographer and a panel that reviewed each scan to identify the day of ovulation. Of the 85 menstrual cycles reviewed, two cycles did not have sufficient data to date ovulation, one cycle showed an incidental dermoid cyst, and 11 cycles showed anovulatory patterns. This left a total of 71 cycles (84%) for which intra-rater reliability between two sonographers for identifying the day of ovulation was high (intraclass correlation coefficient = 0.99, P < 0.0001), and Bland-Altman agreement showed no significant difference in the estimated day of ovulation between the supervising sonographer and the panel (t = -0.28, P = 0.78). Corpus luteum criteria were necessary to help identify the day of ovulation in 14 of 71 cycles (20%). The estimated day of ovulation can be determined reliably on ultrasound by trained sonographers using collapse of the dominant follicle and formation of the corpus luteum based on six to eight scans per cycle.
Yong PJ et al., 2026 · Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC
To provide health care professionals with an evidence-based approach to the management of endometriosis and its associated symptoms. Women and gender-diverse individuals affected by endometriosis. BENEFITS, HARMS, Timely and effective management of endometriosis has the potential to reduce pain, improve fertility and quality of life, and enhance long-term health outcomes. Early intervention may also help mitigate the financial and health system burdens associated with delayed diagnosis and treatment. Published literature was retrieved through searches of PubMed, Ovid, Medline, Embase, Scopus, and the Cochrane Library from August 2010 through December 2025, using relevant MeSH heading and keywords. Results were restricted to systematic reviews, meta-analyses, randomized controlled trials/controlled clinical trials, observational studies, and clinical practice guidelines. Results were limited to English or French language materials. Evidence was supplemented with references from the 2010 Society of Obstetricians and Gynaecologists of Canada guideline No. 244. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional recommendations). Health care providers involved in the care of individuals with endometriosis. Early identification and management of endometriosis can significantly improve patient outcomes, reduce long-term health care costs and improve their quality of life. RECOMMENDATIONS.
Tucker DR et al., 2025 · Human reproduction (Oxford, England) · Free full text on PubMed Central
Is there an association between the somatic loss of PTEN (phosphatase and tensin homolog) and ARID1A (AT-rich interaction domain 1A) and endometriosis disease severity and worse clinical outcomes? Somatic PTEN loss in endometriosis epithelium was associated with greater disease burden and subsequent surgical complexity. Somatic cancer-driver mutations including those involving the PTEN and ARID1A genes exist in endometriosis without cancer; however, their clinical impact remains unclear. STUDY DESIGN, SIZE, This prospective longitudinal study involved endometriosis tissue and clinical data from 126 participants who underwent surgery at a tertiary center for endometriosis (2013-2017), with a follow-up period of 5-9 years. PARTICIPANTS/MATERIALS, SETTING, PTEN and ARID1A loss was assessed using established immunohistochemistry (IHC) methods as proxies for somatic loss by two independent raters. PTEN and ARID1A status for each participant was defined as loss (loss in at least one sample for a participant) or retained (no loss in all samples for a participant). Primary analyses examined associations between PTEN and ARID1A loss and disease burden based on anatomic subtype (superficial peritoneal endometriosis (SUP), deep endometriosis (DE), ovarian endometrioma (OMA)) and rASRM stage (I-IV). Secondary analyses explored associations of PTEN and ARID1A loss with demographics, surgical difficulty, and pain scores (baseline and follow-up). Additionally, using previously published data on KRAS codon 12 mutations for this cohort, we investigated associations between variables in the primary and secondary analyses and acquiring two or more somatic events (PTEN loss, ARID1A loss, or KRAS mutation) in this cohort. The risk of reoperation over the 5-9 years was also examined. MAIN PTEN loss (68.3%; 86 participants) exceeded ARID1A loss (24.6%; 31 participants). Inter-rater reliability was substantial for PTEN (k = 0.69; 95% CI: 0.62-0.77) and ARID1A (k = 0.64; 95% CI: 0.51-0.77). PTEN loss was significantly associated with more severe anatomic subtypes (P < 0.001; participants with SUP only = 46.4%; participants with DE only or OMA only = 72.7%; participants with mixed subtypes = 85.1%), and higher stages (P = 0.024; Stage I = 47.8%; Stage II = 73.7%; Stage III = 80.8%; Stage IV = 81.0%). Results were similar for ARID1A loss, albeit with smaller sample size limiting power. PTEN loss was further associated with non-White ethnicities (P = 0.017) and greater surgical difficulty (more frequent need for ureterolysis) (P = 0.02). There were no differences in pain scores (baseline or follow-up) based on PTEN or ARID1A status. Reoperation was uncommon (13.5% of the cohort), and patterns in reoperation rates based on the presence of somatic alterations did not reach statistical significance. LIMITATIONS, Sequencing was not performed to determine the type of PTEN and ARID1A somatic mutations resulting in loss of expression. These results demonstrate a link between PTEN somatic loss and greater endometriosis disease burden. These findings underscore the potential relevance of PTEN loss and other somatic driver mutations in a future molecular classification of endometriosis. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by Canadian Institutes of Health Research (CIHR) project grant (MOP-142273 and PJT-156084). P.J.Y. was supported by a Health Professional Investigator award from Michael Smith Health Research BC, Canada, and a Canada Research Chair (Tier 2) in Endometriosis and Pelvic Pain. M.S.A. was supported by a Michael Smith Health Research BC Scholar award, and CIHR project grants (369990, 462997, and 456767). The sponsors did not play any role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to [truncated]
Fuldeore MJ et al., 2017 · Gynecol Obstet Invest
Background/aims: To estimate the prevalence of diagnosed endometriosis (DE) in women in the United States and assess the associated symptomatic burden. An online, cross-sectional survey of women aged 18-49 years was conducted from August 6, 2012, through November 14, 2012. Survey data (weighted by age, race, education, income, geographical distribution, and propensity score) were used to estimate the prevalence and symptomatic burden of DE in women in the United States. Weighted logistic regressions were used to assess differences in symptom burden between women with and without endometriosis. The prevalence of DE was estimated at 6.1% (2,922 of 48,020 women surveyed); 52.7% of women were 18-29 years of age when they were diagnosed with endometriosis. Most (86.2%) women experienced symptoms before diagnosis. More women with (vs. without) DE had menstrual pelvic pain/cramping (52.7 vs. 45.2%), non-menstrual pelvic pain/cramping (36.7 vs. 14.3%), infertility (11.6 vs. 3.4%), and dyspareunia (29.5 vs. 13.4%). Women with endometriosis were also more likely to report severe symptoms (OR (95% CI) 2.7 (2.3-3.1) for menstrual pelvic pain/cramping, 2.2 (1.7-2.9) for non-menstrual pelvic pain/cramping, and 2.4 (1.8-3.2) for dyspareunia). The prevalence of DE among US women is notable, and affected women experience a substantial symptom burden.
Bulun SE et al., 2019 · Endocr Rev · Free full text on PubMed Central
Pelvic endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects primarily pelvic tissues, including the ovaries. It is caused when shed endometrial tissue travels retrograde into the lower abdominal cavity. Endometriosis is the most common cause of chronic pelvic pain in women and is associated with infertility. The underlying pathologic mechanisms in the intracavitary endometrium and extrauterine endometriotic tissue involve defectively programmed endometrial mesenchymal progenitor/stem cells. Although endometriotic stromal cells, which compose the bulk of endometriotic lesions, do not carry somatic mutations, they demonstrate specific epigenetic abnormalities that alter expression of key transcription factors. For example, GATA-binding factor-6 overexpression transforms an endometrial stromal cell to an endometriotic phenotype, and steroidogenic factor-1 overexpression causes excessive production of estrogen, which drives inflammation via pathologically high levels of estrogen receptor-β. Progesterone receptor deficiency causes progesterone resistance. Populations of endometrial and endometriotic epithelial cells also harbor multiple cancer driver mutations, such as KRAS, which may be associated with the establishment of pelvic endometriosis or ovarian cancer. It is not known how interactions between epigenomically defective stromal cells and the mutated genes in epithelial cells contribute to the pathogenesis of endometriosis. Endometriosis-associated pelvic pain is managed by suppression of ovulatory menses and estrogen production, cyclooxygenase inhibitors, and surgical removal of pelvic lesions, and in vitro fertilization is frequently used to overcome infertility. Although novel targeted treatments are becoming available, as endometriosis pathophysiology is better understood, preventive approaches such as long-term ovulation suppression may play a critical role in the future.
Carey ET et al., 2025 · Obstetrics & Gynecology
Endometriosis is an estrogen-dependent, chronic inflammatory disorder characterized by the presence of endometrium-like tissue outside the uterus, affecting approximately 10% of individuals of reproductive age. It contributes to chronic pelvic pain, dysmenorrhea, and subfertility, resulting in substantial societal economic burdens. Genetic and environmental risk factors have been identified, and recent research suggests that endometriosis functions as a systemic disease affecting nonreproductive systems and increasing susceptibility to other health conditions. Various phenotypes-superficial peritoneal endometriosis, ovarian endometriomas, and deep endometriosis-may develop under different mechanisms, yet the relationship between these presentations remains unclear. Diagnosis relies on clinical evaluation, imaging, and surgical staging, and the advent of advanced ultrasonography and magnetic resonance imaging has helped to enhance accuracy. Although medical management focuses on hormonal modulation to alleviate symptoms, surgical intervention remains a critical tool for refractory symptoms. Postoperative care and patient education are essential to manage recurrence and to improve quality of life. Current research emphasizes the need for comprehensive, interdisciplinary approaches to endometriosis management, incorporating novel diagnostic tools, diverse therapeutic avenues, and patient-centered care models. Addressing disparities in treatment access is essential to improving outcomes. To achieve this, recruiting and analyzing data from racially, socioeconomically, and geographically diverse cohorts will reveal how disease presentation and treatment efficacy vary across populations. Continued efforts in research and health care policy are necessary to develop effective and personalized strategies in managing endometriosis.
