(1073) Placenta Accreta Spectrum and Endometriosis

Objective: The chronic pelvic inflammation and endometrial dysfunction that characterize endometriosis may predispose those affected by it to placenta accreta spectrum (PAS). Prior small studies suggest there may be an association between endometriosis and PAS. We aimed to evaluate this association in a nationwide sample to better understand the etiology and risk factors for PAS.

Study Design:

We performed a retrospective cohort study using the U.S. National Inpatient Sample from 2017-2020 including individuals delivering after 20 weeks’ gestation. ICD-10 codes were used to determine exposure and outcomes. A logistic regression model controlling for confounding variables was constructed. As placenta previa is a mediating effect, it was not included as a confounding factor in our main regression model. A mediation analysis was performed using the counterfactual approach. Data were weighted according to NIS reported sampling weights.

Results:

Of 14,154,044 (2,833,010 unweighted) individuals included, 0.12% had PAS and 0.15% had endometriosis. Baseline characteristics are shown in Table 1. In the unadjusted regression model, endometriosis was associated with an increased odds of PAS (OR 5.4; 95% CI 3.7-7.8) (Table). When controlling for confounding factors (age, prior cesarean section, and obesity) the odds of having PAS was higher in patients with endometriosis (OR 3.2, 95% CI 2.3-4.8, p=0.01). In the mediation analysis, placenta previa was found to be an indirect mediator (percent of the total effect that is mediated is 0.49). A second regression model including placenta previa as a covariate was constructed and included in the Table. 

Conclusion:

There is an association between endometriosis and PAS. Further research into the causal pathway between these two disease entities is warranted and may help shed further light onto the role of inflammatory mediators in the development of PAS.