Background/Objectives: Chronic endometritis (CE) is a subclinical inflammation of the endometrium that affects female fertility. Although awareness of its impact on reproductive outcomes has increased significantly, clinical management—especially the diagnostic value of hysteroscopy and the effectiveness of perioperative antibiotic prophylaxis in improving fertility—remains unclear. Methods: This retrospective analysis involved 136 infertile women (30–44 years) who underwent diagnostic hysteroscopy between 2022 and 2023 at the Military Institute of Medicine in Warsaw. Women with intrauterine pathologies or other infertility factors were excluded. Hysteroscopic indicators of chronic endometritis (CE) included micropolyps and endometrial hyperemia. Endometrial biopsies were stained with CD138 and CE was diagnosed based on ≥5 plasma cells per 10 high-power fields. A single oral dose of azithromycin was administered post-procedure and pregnancy outcomes were assessed 12 months later. Results: CE was histologically confirmed in 29.2% of patients. The presence of micropolyps demonstrated a strong correlation with CE (p < 0.0001), although CE was also found in 21% of patients with normal hysteroscopic findings. While CE status did not significantly influence pregnancy rates, patients who received azithromycin exhibited a significantly higher conception rate (53% vs. 21%, p = 0.022). Additionally, secondary infertility was associated with higher reproductive success compared to primary infertility (54% vs. 24%, p = 0.022). Conclusions: Micropolyps are a specific hysteroscopic marker of CE. However, histologic inflammation markers may be present even in the absence of abnormal hysteroscopic findings. Furthermore, the routine use of antibiotic prophylaxis is associated with improved reproductive outcomes.