Background <p>Hysteroscopy is not a standard diagnostic procedure for infertility. The objective was to present and compare obstetric outcomes in women undergoing office hysteroscopy (OH) in the course of diagnostic evaluation and ineffective treatment of infertility due to various underlying factors.</p> Methods <p>Obstetric outcomes, including rates of live births, clinical and biochemical pregnancies, and time to conception, were retrospectively compared within four preoperative diagnosis groups (idiopathic infertility, uterine polyp, uterine factors other than polyps, and other conditions) and four postoperative diagnosis groups (uterine polyp, clinical features of chronic endometritis (CE), uterine factors, and other findings), while taking into account the immunohistochemical status of CE, defined by the presence or absence of plasma cells as positive, negative, or unknown if not examined.</p> Results <p>The study included 334 women with a mean age of 35.39 (± 4.51) years, comprising 161 (48.20%) with primary infertility and 173 (51.80%) with secondary infertility. Considering the preoperative diagnoses, the relatively highest percentage of live births was observed in women undergoing hysteroscopy due to recurrent miscarriages, while the lowest rate of achieved pregnancies was recorded in women with suspected polyps (<i>p</i> = 0.012). In the case of a positive CE status and empirical antibiotic treatment, the relatively highest live birth rate was in women with idiopathic infertility, while the lowest conception rate was recorded in women with suspected polyps (<i>p</i> = 0.011). Regarding hysteroscopic findings, the relatively highest percentage of achieved pregnancies occurred in women undergoing resection of a uterine septum or intrauterine adhesions, while the lowest was observed in those following polypectomy (<i>p</i> = 0.036). No differences in obstetric outcomes were observed depending on CE status regarding intraoperative diagnoses. None of the hysteroscopic findings were independent prognostic factors for live birth.</p> Conclusions <p>In planning OH for the unsuccessful management of idiopathic infertility, verifying immunohistochemical CE status could facilitate treatment and relatively improve obstetric outcomes if positive. When a suspected polyp is accompanied by CE, the administration of antibiotic therapy following OH aimed at treating CE might not improve obstetric outcomes. The removal of a partial uterine septum or intrauterine adhesions could enhance the rate of achieved pregnancies, regardless of CE status.</p>