Endometrial Polyps and Subfertility in Women Under 40: Pathophysiology, Fertility Outcomes, and Clinical Management

Background and Objectives: Endometrial polyps are common in women presenting with subfertility, yet uncertainty persists regarding which lesions warrant removal and how best to integrate hysteroscopic management with contemporary fertility treatment pathways. This narrative review synthesizes current evidence on pathophysiological mechanisms, diagnostic approaches, fertility outcomes, and practical clinical management for women under 40 years of age. Materials and Methods: PubMed/MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library were searched for English-language human studies published between January 2005 and December 2024. From 2352 records identified, 83 studies were included (8 randomized controlled trials, 12 systematic reviews/meta-analyses, 21 prospective cohort studies, 34 retrospective cohort studies, 5 case-control studies, and 3 clinical guidelines). Evidence was synthesized thematically using a narrative approach. Results: Across treatment modalities, hysteroscopic polypectomy was consistently associated with improved fertility outcomes. The landmark Pérez-Medina randomized trial reported a relative risk of 2.1 (95% CI 1.5–2.9) for pregnancy after polypectomy before intrauterine insemination. For IVF/ICSI, reported clinical pregnancy rates after polypectomy range from 53–72% and live birth rates from 43–66%. Proposed mechanisms include mechanical interference, chronic inflammation with cytokine dysregulation, altered endometrial receptivity (including HOXA10/HOXA11 dysregulation), and impaired decidualization. Conclusion: Current evidence supports hysteroscopic polypectomy as an effective intervention to improve fertility outcomes in subfertile women with endometrial polyps, particularly prior to intrauterine insemination and IVF/ICSI. Contemporary guidance (including the 2024 SOGC guideline) favors polypectomy regardless of polyp size. Future research should clarify molecular predictors of polyp-associated infertility, optimal timing relative to fertility treatment, and long-term reproductive outcomes.