{"paper_id":"2e19bd1b-f5a2-4ba7-ac81-69c63682a896","body_text":"~ 1 ~ \n \nISSN Print: 2664-8393 \nISSN Online: 2664-8407 \nImpact Factor (RJIF): 5.75 \nIJGS 2026; 8(1): 01-03 \nwww.gynaecologyjournal.net \nReceived: 02-11-2025 \nAccepted: 05-12-2025 \n \nFDH Olalere \nDepartment of Obstetrics and \nGynecology, Lagos State \nUniversity College of Medicine, \nIkeja, Lagos, Nigeria \n \nK Durosinmin \nDepartment of Radiology, \nGeneral Hospital Lagos, Odan. \nLagos Island, Lagos. Nigeria \n \nTO Kuye-Kuku \nDepartment of Obstetrics and \nGynecology, Lagos State \nUniversity College of Medicine, \nIkeja, Lagos, Nigeria \n \nHA Olalere \nDepartment of Obstetrics and \nGynecology, Lagos State \nUniversity College of Medicine, \nIkeja, Lagos, Nigeria \n \nJO Imaralu \nDepartment of Obstetrics and \nGynecology, Babcock University \nTeaching Hospital, Nigeria \n \nHA Olalere \nDepartment of Obstetrics and \nGynecology, Eko University of \nMedicine and Health Sciences, \nIjanikin, Lagos, Nigeria \n \nF Egwuatu \nEmbryology Department, Triple \nH Fertility Hub & Specialist \nHospital, Surulere Lagos, \nNigeria \n \nHA Olalere \nDepartment of Obstetrics and \nGynecology, Ain Sham \nUniversity, Cairo, \nEgypt \n \nBA Oye-Adeniran \nDepartment of Obstetrics and \nGynecology, College of Medicine, \nIdi-Araba, Lagos, Nigeria \n \n \n \n \n \nCorresponding Author: \nFDH Olalere \nDepartment of Obstetrics and \nGynecology, Lagos State \nUniversity College of Medicine, \nIkeja, Lagos, Nigeria \nFolasade.olalere@lasucom.edu.ng \n \nEndometrial cavity fluid: Clinical significance, \npathophysiology and implications for fertility and \nassisted reproductive technology: A narrative review \n \nFDH Olalere, K Durosinmin, TO Kuye-Kuku, HA Olalere, JO Imaralu, \nHA Olalere, F Egwuatu, HA Olalere and BA Oye-Adeniran\n \n \nDOI: https://www.doi.org/10.33545/26648393.2026.v8.i1a.50  \n \nAbstract \nEndometrial cavity fluid (ECF) is a frequently encountered ultrasonogra phic finding in gynecological \nand fertility practice. While small, transient amounts of fluid may be physiological, persistent or \nexcessive accumulation is often associated with underlying pathology and adverse reproductive \noutcomes. The presence of ECF has generated particular interest in infertility a nd assisted reproductive \ntechnology (ART), where its impact on implantation and pregnancy ou tcomes remains controversial. \nThis narrative review explores the etiology, pathophysiology, diagnostic assessment, and clinical \nimplications of endometrial cavity fluid, with emphasis on its assoc iation with endometriosis, tubal \ndisease, uterine infection, and IVF/ICSI outcomes. Emerging evidence on endometrial fluid as a potential \nnon-invasive biomarker source is also discussed. \n \nKeywords: Endometrial cavity fluid, infertility, endometriosis, hysteroscopy, in vitro fertilization \n \nIntroduction \nThe endometrium is the specialized mucosal lining of the uterus, a hollow muscular organ that \nsupports embryo implantation and fetal development  [1] . Cyclical changes in endometrial \nstructure and secretory activity are essential for reproductive success.  The presence of fluid \nwithin the endometrial cavity, however, may disrupt this finely regulated environment. \nEndometrial cavity fluid is increasingly detected with the widespread use o f high-resolution \ntransvaginal ultrasonography  [11] . Although minimal fluid can be a normal physiological \nfinding, particularly around ovulation, persistent or excessive ECF has been associated with \ninfertility, pelvic pathology, and poor outcomes following assisted repro duction. \nUnderstanding the clinical relevance of ECF is therefore essential for gynecologist s and \nfertility specialists. \n \nDefinition and Ultrasonographic Assessment of Endometrial Cavity Fluid  \nEndometrial cavity fluid is defined sonographically as an echoluscent or hypoechoic area \ndistending the uterine cavity, typically visualized in the sagittal plane. It is often described as \na central fluid collection separating the anterior and posterior endometrial linings. \nThe degree of fluid accumulation is commonly quantified using the a nteroposterior diameter \n(APD), measured as the maximal distance between the opposing endometrial surfaces. In the \npresence of fluid, true endometrial thickness is calculated by subtracting  the maximal fluid \ndiameter from the total endometrial measurement between the myometrial-end ometrial \ninterfaces. These parameters allow standardized assessment and comparison across studies. \n \nEtiology of Endometrial Cavity Fluid \nThe etiology of ECF remains multifactorial and, in some cases, controversial. Recognized \nassociations include: \n \nTubal Pathology \nHydrosalpinx is one of the most established causes of ECF  [1, 2] . Retrograde flow of \ninflammatory tubal fluid into the uterine cavity can lead to persistent fluid accumulation, which \nis toxic to embryos and adversely affects implantation.\nInternational Journal of Gynaecology Sciences  2026;  8(1): 01-03 \n \n\n\n \n~ 2 ~ \nInternational Journal of Gynaecology Sciences https://www.gynaecologyjournal.net \n \nUterine and Endometrial Factors \nSubclinical endometritis, uterine adhesions, retained \nproducts, and intrauterine foreign bodies may contribute to \nfluid accumulation through chronic inflammation and altered \nendometrial permeability. \n \nEndometriosis \nEndometriosis is an estrogen-dependent chronic \ngynecological disease characterized by the presence of \nendometrial-like tissue outside the uterine cavity  [3, 4] . \nAffecting approximately 10-32% of women of reproductive \nage, it is strongly associated with infertility and pelvic pain. \nAlthough laparoscopy remains the gold standard for \ndiagnosis, there is increasing interest in non-invasive \ndiagnostic approaches. \nChronic inflammation, altered cytokine profiles, and \nabnormal endometrial secretory function in women with \nendometriosis may contribute to abnormal fluid dynamics \nwithin the uterine cavity. Endometrial cavity fluid has \ntherefore been investigated as a potential biological medium \nfor biomarker discovery in this population. \n \nOvulatory and Hormonal Factors \nPolycystic ovarian syndrome (PCOS), anovulation, and \nestrogen-progesterone imbalance may also predispose to ECF \nthrough altered endometrial maturation and glandular \nsecretion. \n \nPhysiological Versus Pathological Fluid \nSmall volumes of endometrial fluid may be observed during \nthe periovulatory period or immediately following \nmenstruation and are generally considered physiological. In \ncontrast, persistent fluid, fluid associated with pain, bleeding, \nor infection, or fluid detected during embryo transfer cycles \nis more likely to be pathological and clinically significant. \nFluid containing blood may suggest cyst rupture, endometrial \ntrauma, or ectopic pathology, while purulent fluid raises \nsuspicion of infection requiring antibiotic therapy. \n \nEndometrial Cavity Fluid and Endometriosis: Diagnostic \nImplications \nEndometriosis remains a diagnostic challenge due to its \nheterogeneous presentation and reliance on surgical \nconfirmation. Non-invasive tests, including serum \nbiomarkers such as CA-125 and imaging modalities, lack \nsufficient sensitivity and specificity, particularly in early \ndisease. \nProteomic and molecular studies have demonstrated that \nendometrial fluid contains cytokines, growth factors, and \nproteins reflective of the intrauterine environment.^8-10 \nEndometrial fluid aspirate can be obtained using an embryo \ntransfer catheter during routine gynecological examination \nwithout anesthesia. This minimally invasive approach has \nshown promise as a source of biomarkers for endometriosis, \nalthough further validation is required before clinical \napplication. \n \nImpact of Endometrial Cavity Fluid on IVF and ICSI \nOutcomes \nThe effect of ECF on ART outcomes remains controversial. \nSeveral studies have reported reduced implantation and \npregnancy rates in the presence of persistent ECF, \nparticularly when fluid is present at the time of embryo \ntransfer [1, 2] . Proposed mechanisms include mechanical \nflushing of embryos, embryotoxic effects of inflammatory \nmediators, and impaired endometrial receptivity. \nConversely, some studies suggest that transient fluid that \nresolves before embryo transfer may not adversely affect \noutcomes. As a result, management strategies vary widely \namong fertility centers. \n \nManagement Strategies \nCommon approaches to ECF in ART include postponement \nof embryo transfer with a freeze-all strategy, treatment of \nunderlying infection, surgical management of hydrosalpinx, \nand hysteroscopic evaluation of the uterine cavity. \nAspiration of endometrial fluid immediately prior to embryo \ntransfer using an embryo transfer catheter has been described \nas a simple and potentially effective intervention  [11] . \nHowever, this approach may be associated with \npsychological distress due to cycle cancellation or repeated \nprocedures, underscoring the need for individualized patient \ncounseling. \n \nIVF Protocol Considerations \nVarious ovarian stimulation protocols, including long GnRH \nagonist, GnRH antagonist, and microdose flare-up protocols, \nare used in patients with ECF based on individual \ncharacteristics. Monitoring with serial transvaginal \nultrasound is essential. Triggering is typically achieved with \nGnRH agonist or human chorionic gonadotropin, followed by \noocyte retrieval 36 hours later. Many centers adopt a freeze-\nall approach in the presence of significant ECF. \n \nFuture Directions \nFurther research is needed to clarify the threshold at which \nECF becomes clinically significant, to standardize diagnostic \ncriteria, and to validate endometrial fluid biomarkers for non-\ninvasive diagnosis of endometriosis and other uterine \npathologies. \n \nConclusion \nEndometrial cavity fluid represents a complex clinical \nfinding with implications for fertility, gynecological health, \nand assisted reproduction. While small, transient fluid \ncollections may be physiological, persistent or pathological \nECF warrants thorough evaluation. Advances in imaging, \nhysteroscopy, and molecular analysis of endometrial fluid \nhold promise for improved diagnosis and management of \ninfertility-related conditions. \n \nReferences \n1. 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