Prevalence and risk factors of intrauterine adhesions in women with a septate uterus: a retrospective cohort study

Research question: What are the prevalence and risk factors of intrauterine adhesions (IUA) in patients with a septate uterus? Design: In this retrospective cohort study, patients with a septate uterus who underwent septum resection between 2015 and 2020 were analysed. Two-dimensional transvaginal ultrasonography plus hysteroscopy was used to diagnose uterine septum or IUA. The prevalence and risk factors for IUA in patients with a septate uterus were examined. Results: Among 522 eligible patients with a septate uterus, 165 patients were diagnosed with IUA (prevalence 31.6% [95% CI 27.7 to 35.5%]). In the multivariable logistic regression analysis of risk factors for IUA, patients who had experienced one or more miscarriages were more likely to have IUA than patients who had not (OR 3.38, 95% CI 1.96 to 5.83, P < 0.001, and OR 2.55, 95% CI 1.24 to 5.23, P = 0.011, respectively). Patients who underwent one or more dilatation and curettage (D&C) procedures had a significantly increased risk of IUA compared with patients who did not (OR 3.42, 95% CI 1.87 to 6.26, P < 0.001, and OR 3.99, 95% CI 1.93 to 8.26, P < 0.001, respectively). For patients with a history of miscarriage or D&C, the prevalence rates of IUA were 46.5% (95% CI 40.6 to 52.4%) and 44.0% (95% CI 38.5 to 49.5%), respectively. Conclusion: Nearly one-third of patients with a septate uterus have concomitant IUA. A previous miscarriage or D&C is an important risk factor for IUA in patients with a septate uterus.