Clinical Characterization of Genital Tract Malformations: A Retrospective Cohort Study on Associations with Endometriosis and Pregnancy Outcomes

Purpose: To characterize the clinical phenotypes of congenital genital tract malformations and evaluate their associations with endometriosis (EM) and fertility outcomes. Patients and Methods: This retrospective cohort study analyzed 306 women with congenital genital tract anomalies treated at a tertiary hospital (2011– 2022). Anatomical classifications (obstructive vs non-obstructive), laparoscopically confirmed EM, and postoperative fertility were assessed. Infertility was defined as failure to achieve a clinical pregnancy after ≥ 12 months of unprotected intercourse. Results: The overall EM prevalence was 18.3% (56/306), which was significantly higher in the obstructive group than in the non-obstructive group (42.86% vs 16.49%, P=0.006). Patients with obstructive malformations developed EM at a younger age (25.22± 4.02 vs 28.46± 4.49 years, P=0.049) and had more severe EM stages (P=0.027). Preoperative infertility rates were comparable between the obstructive (38.10%) and non-obstructive (36.84%) groups (P=1.0). However, within the non-obstructive group, the infertility rate was significantly higher in women with EM than in those without (53.32% vs 33.19%, P=0.004). Surgical intervention significantly reduced infertility rates, with the most substantial benefit observed in the non-obstructive malformation + EM subgroup (Absolute Risk Reduction=48.94%, Number Needed to Treat=2). Vaginal septa and residual uterine horns were associated with the highest infertility risks. Conclusion: Obstructive malformations are associated with early-onset, severe EM, likely facilitated by retrograde menstruation. Non-obstructive variants are linked to insidious EM progression and diagnostic delay. Timely surgical correction, particularly for septal anomalies, significantly improves fertility. Integrating MRI into diagnostic protocols and maintaining a high index of suspicion for occult malformations in adolescents with EM are crucial. Keywords: endometriosis, genital tract malformations, infertility, vaginal septum, uterine septum, pregnancy outcomes