Cesarean Scar Endometriosis Incidence and Risk Factors After Primary Cesarean Delivery

Abstract

Study Objective: Cesarean scar endometriosis (CSE), sequelae of cesarean section, has been reported to occur in 0.03%-0.45% in small cohort reports. The true incidence of AWE is currently unknown. This study aims to identify the true incidence of CSE and risk factors for its development using a large nationwide database. Design: A retrospective study to measure the incidence of CSE in patients who underwent primary cesarean delivery (CD) between 2010 and 2023. Cases of primary CD were identified using the national Vizient Clinical Database and followed in time for diagnosis of CSE. The incidence rate (95% confidence interval) was calculated as the number of cases of CSE during the study period divided by the person-time-at-risk following primary CD. Risk factors for AWE were measured using the odds ratio (95% confidence interval). Setting: National database that collects de-identified information from over 500 academic and community hospitals across the US. Patients or Participants: Study cohort of patients that underwent primary CD between 2010 and 2023 derived from a population-based data source. Diagnoses were identified using ICD-codes. Measurements or Main Results: A total of 2,356,503 cases of CD comprised the study cohort. Demographics included median age [31.0 years (interquartile range: 27, 35)]. CSE was diagnosed in 18,030 (0.8%) of patients and 93% (n=16812) occurred after primary CD. The median time to diagnosis was 2.9 years (1.46, 4.91). The population incidence rate was 1.70/1000 person-years (1.67, 1.72) in women after primary CD. Incidence rates rose with increasing maternal age at primary CD: 18-24 years [0.90/1000 person-years (0.86, 0.95)], 25-29 years [1.48/1000 person-years (1.43, 1.53)], 30-34 years [1.79/1000 person-years (1.75, 1.84)], 35-39 years [2.21/1000 person-years (2.15, 2.27)], and 40 years and older [2.42/1000 years (2.31,2.54)]. The increasing risk with maternal age was statistically significant for a positive linear trend (p trend p < 0.001). Patients at increased risk for AWE were privately insured [2.11 (2.03, 2.18)], had a smoking status at CD [1.73 (1.66, 1.81), and had diabetes disease at the time of CD 26.19 [25.31, 27.10]. Conclusion: This study estimates the population incidence of CSE is 1.7/1000 person-years. This is the first study to calculate the true incidence of CSE. This is something that can be incorporated into the counseling for cesarean deliveries as a complication.