JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):138
Poster Presentation
29^th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263775

P-126. Impact of Chronic Endometritis on Reproductive Outcomes in Women with Recurrent Implantation Failure

Drielly dos Reis Franzoi¹, Geovanda Alves Vasconcelos¹, Elisa Mitsue Chibana¹, Jaqueline Sayuri Asato¹, Maria Monica Pereira¹

¹ Centro Universitário São Camilo - São Paulo - SP – Brasil

Objective: This study aimed to analyze the clinical repercussions of subclinical chronic endometritis (SCE) on repeated implantation failure (RIF), as well as its diagnosis and treatment.
Methods: This narrative review was conducted using the PUBMED and LILACS databases, focusing on studies from the last five years. The search strategy was "endometritis" AND "embryo implantation", identifying 71 articles. Inclusion criteria were primary studies in English, Portuguese, or Spanish, full text available, and involving women with SCE. Two reviewers selected studies independently; conflicts were resolved by a third author. Sixteen studies were included.
Results: In this review, 16 studies were included, encompassing a total of 6,415 patients. The prevalence of chronic endometritis (CE) in women with repeated implantation failure (RIF) ranged from 14% to 67.5%, with diagnosis confirmed by immunohistochemistry to detect CD138⁺ plasma cells. Positivity criteria varied between ≥1 cell per 10 high-power fields, ≥3 cells per section, and ESPDI ≥0.25. Hysteroscopy showed low correlation with CD138⁺ detection, being relevant only in the presence of micropolyps (r=32; p<0.001). CE was associated with poorer reproductive outcomes. Patients with RIF and CE had lower clinical pregnancy rates versus patients without CE (20% vs. 46.85%; p=0.04), and CD138⁺ positivity was identified as an independent risk factor for implantation failure. Furthermore, CE showed association with clinical factors such as parity ≥2, endometrial polyps, and multiple uterine surgeries (p<0.05). Local immunological changes were observed, such as increased inflammatory cell infiltration and increased expression of epithelial–mesenchymal transition markers, indicating an impact on endometrial receptivity. In addition, CE was related to endometrial dysbiosis, marked by decreased Lactobacillus spp. and increased bacteria such as Gardnerella, Enterococcus, and Phyllobacterium, affecting immunometabolic pathways and Th1/Th17 cell regulation, contributing to endometrial immune imbalance. Therapeutic interventions demonstrated clinical benefits. Treatment with oral antibiotics (doxycycline, metronidazole, levofloxacin) achieved histological cure rates of up to 89.4%, with improvement in endometrial inflammation and increased clinical pregnancy rates in subsequent embryo transfer cycles. The combination of antibiotics with intrauterine perfusion showed positive effects, with higher clinical pregnancy rates compared to antibiotics alone (50% vs. 30%; p<0.001) and lower early pregnancy loss. Supplementation with lactoferrin and vaginal Lactobacillus was also effective, being associated with higher clinical pregnancy rates compared to women without supplementation (71.4% vs. 22.2%; OR=8.75; p=0.029) and live birth rates (57.1% vs. 11.1%; OR=10.67; p=0.046). Similarly, the use of GnRH agonists (GnRH-a) after antibiotic therapy was associated with better clinical pregnancy outcomes (42.37% vs. 24.05%; p=0.022). In refractory cases, intrauterine infusion of platelet-rich plasma (PRP) contributed to histological cure and increased implantation rates (54.3% vs. 21.1%; p=0.018) and clinical pregnancy rates (75.0% vs. 38.5%; p=0.038). The meta-analysis revealed a significant association between CE and lower clinical pregnancy rates (OR=0.45; 95% CI: 0.29–0.71; p<0.001), with moderate heterogeneity among studies (I²=56%). No relevant publication bias was identified.
Conclusion: The relationship between CE and RIF has been widely studied in assisted reproduction. However, the lack of standardization in diagnostic methods for CE makes it difficult to accurately assess this association. Nevertheless, studies have shown a correlation between these two factors, evidenced by the positive effects of antibiotics used for CE and the identification of typical disease markers (CD138) as independent risk factors for RIF. Further studies are needed to clarify the pathophysiology of this association and to assess the effectiveness of probiotic treatments.