Insights from an observational matched case-control study on the association between endometriosis and benign uterine disorders in infertile patients

The link between endometriosis and other medical conditions is gaining attention. Such insights could enhance clinical approaches to manage the disease and potentially reveal new, unrecognized mechanisms of its development. The aim of this study was to assess the association between endometriosis and four benign uterine conditions - adenomyosis, endometrial polyps, uterine fibroids, and non-obstructive Müllerian malformations - each analyzed separately. A retrospective analysis was conducted on n = 200 infertile patients with a history or current diagnosis of endometriosis, who were matched 1:1 by age and study period to n = 200 infertile individuals without endometriosis, whose partners had severe male infertility. These patients, representing the general population, were used as controls. The evaluation considered a history of surgery or current diagnosis of adenomyosis, endometrial polyps, uterine fibroids, and non-obstructive Müllerian malformations. Baseline characteristics were similar between the two groups, except for BMI. The adjusted Odds Ratios (ORs) for the association between endometriosis and adenomyosis, endometrial polyps, uterine fibroids, and non-obstructive Müllerian malformations were 12.7 (95%CI: 4.9-33.0), 3.5 (95%CI: 1.5-8.1), 6.0 (95%CI: 2.2-17.0), and 3.5 (95%CI: 0.7-17.5), respectively. No subgroup of patients with endometriosis was identified for whom the association was stronger. These findings indicate a significant association between endometriosis and several benign uterine conditions, suggesting that further investigation is needed to understand the underlying mechanisms.