Association Between Endometriosis and Congenital Uterine Malformations: A Single-Center Retrospective Study

STUDY OBJECTIVE: The association between endometriosis and congenital uterine anomalies (CUAs) has been discussed for decades, but existing evidence about this association is scarce. Our study aimed to evaluate the prevalence of CUAs in women with endometriosis and to identify specific characteristics in women with both CUAs and endometriosis in a large cohort of patients. DESIGN: This is a retrospective single-center observational study conducted between January 2006 and June 2021. SETTING: Swiss tertiary hospital. PATIENTS: Women with histologically confirmed endometriosis at laparoscopy. INTERVENTIONS: All women included in this study underwent a preoperative 2-dimensional ultrasound by an experienced sonographer. In cases of suspected intrauterine pathology, bleeding disorders, or infertility, an additional hysteroscopy was performed. MEASUREMENTS AND MAIN RESULTS: Of 1566 women with histologically confirmed endometriosis, 93 were diagnosed as having CUAs (5.9%). The most frequent malformations were U1c (arcuate uterus) (41 of 93, 44.1%), U2a (partial septate uterus) (19 of 93, 20.4%), U3b (complete bicorporeal uterus) (17 of 93, 18.3%), and U3a (partial bicorporeal uterus) (10 of 93, 10.8%). Women with both CUAs and endometriosis were more frequently diagnosed as having endometriosis revised American Society for Reproductive Medicine stage IV (p = .017) and presence of dysmenorrhea (p = .019) in comparison with women with endometriosis and a morphologically normal uterus. CONCLUSIONS: To the best of our knowledge, this is the largest endometriosis population examined for the prevalence of CUAs. According to our findings, the prevalence of CUAs in women with endometriosis does not seem to be higher than in the general population. However, women with CUAs and endometriosis are more likely to have severe endometriosis (revised American Society for Reproductive Medicine stage IV) and dysmenorrhea than patients with endometriosis without CUA.