Background: Chronic Endometritis (CE) is a subtle pathology, likely infectious in most cases, with a negative impact on the female fertility, but often overlooked even among fertility specialists. The purpose of the study is to demonstrate the predominant infectious nature of CE and to find the best therapeutic option by comparing the results of oral antibiotic therapy versus intrauterine antibiotic infusion in patients with CE undergoing IVF procedures. The objective was to compare the cure rate of CE—defined as the percentage of patients without CE at the test of cure, between the two groups and, the hysteroscopic aspect with the positive CD 138 staining. Methods: This was a prospective, case—control study that took place in a single university fertility clinic, in Oradea, Romania and included 57 patients with CE divided into 2 groups: orally administered antibiotics group who received a combination of antibiotics compared to intrauterine infusion group who received intrauterine infusion of antibiotic. Chronic Endometritis was diagnosed through hysteroscopy and immunohistochemistry for CD 138. Patients in both groups were tested for CE twice to evaluate the cure rate after oral combination antibiotic therapy versus intrauterine infusion of antibiotic. Results: Out of 115 patients with endometrial biopsies 57 tested positive for CE, with a 49.6% chronic endometritis prevalence. Among the group that was administered oral antibiotics, 11 patients (45.83%) experienced CE resolution after triple antibiotic therapy. Of the intrauterine infusion group, 25 patients (89.29%) presented negative results (p 0.0020). The normal hysteroscopic aspect had a similar prevalence in the patients with immunohistochemical positive and negative CD 138. Conclusions: Our study demonstrated the effectiveness and superiority of intrauterine antibiotic infusion over the use of oral combination antibiotic therapy for CE cure. Trial Registration: ISRCTN17542620/14.09.2022.

Background and Objectives: Recurrent implantation failure (RIF) affects 10% of couples undergoing in vitro fertilization (IVF), spurring exploration into tailored treatments to enhance implantation rates. Maternal immune tolerance towards embryos, particularly killer-cell immunoglobulin-like receptors (KIRs) on natural killer (NK) cells, is a focal point in RIF research. Materials and Methods: This retrospective cohort study, conducted at fertility clinic in Oradea, Romania, involved 65 infertile couples undergoing IVF treatment between January 2022 and December 2023. Couples were divided into two groups: KIR AA (Group A) and KIR Bx (Group B). Results: Factors such as age, type of infertility, oocytes retrieved, embryos produced, pregnancy rates in Group A without and with immunomodulatory treatment were documented. Group A, receiving immunomodulatory treatment, achieved a pregnancy rate of 47.8%, significantly higher than the 23.73% rate without treatment (p = 0.008). Group B had a higher mean patient age than Group A. However, miscarriage rates did not significantly differ between Group A with treatment and Group B (p = 0.2457), suggesting comparable outcomes with immunomodulation. Conclusions: The impact of immunological factors on recurrent implantation failure is being more and more emphasized and warrants the attention of specialists in human reproduction. Uterine natural killers and their function though KIR receptors deserve particular attention as immunomodulatory treatment may improve pregnancy rates in patients with KIR AA haplotype.

Chronic endometritis (CE) is a persistent, often asymptomatic inflammatory condition of the endometrium, increasingly recognized as a potential contributor to infertility and recurrent implantation failure. Despite its clinical significance, CE remains underdiagnosed due to a lack of standardized diagnostic criteria and its subtle clinical presentation. Objective: This review aims to synthesize the current evidence on the pathophysiology, diagnosis, and treatment of CE, highlighting its impact on reproductive outcomes and the effectiveness of therapeutic interventions. A comprehensive literature review was conducted, analyzing 85 peer-reviewed studies published in the last decade, of which 65 were deemed relevant and retained for further analysis. These studies were selected based on their relevance to the pathophysiology, diagnostic methodologies, and treatment outcomes for CE, focusing on their implications for fertility and assisted reproductive technologies (ARTs). The findings suggest that CE is associated with impaired endometrial receptivity, increased inflammatory markers, and reduced implantation and pregnancy rates with ARTs. Histopathological assessment using CD138 immunostaining remains the gold standard for diagnosis, while hysteroscopy and molecular microbiological techniques provide complementary diagnostic value. Antibiotic treatment has been shown to significantly improve implantation rates and pregnancy outcomes, particularly in women with recurrent implantation failure. Emerging therapies, including probiotics and regenerative medicine approaches, are being explored as potential adjuncts to the conventional treatment. Early and accurate diagnosis of CE is essential for optimizing reproductive outcomes. Standardized diagnostic protocols and individualized treatment strategies are crucial for improving implantation success and pregnancy rates in affected women. Future research should focus on refining the diagnostic methods and exploring novel therapeutic options to enhance endometrial health and fertility outcomes.