Inflammatory features in placentas of women with endometriosis and their relation to maternal and neonatal outcomes

Background: Endometriosis, affecting 6–10 % of reproductive-age women, is linked to infertility and adverse pregnancy outcomes. Its association with immune dysregulation and potential role in pregnancy complications remain unclear. Placental histopathology can provide insight into intrauterine inflammatory processes. This study examines the relationship between endometriosis and placental pathology to explore mechanisms underlying adverse pregnancy outcomes. Methods: A retrospective cohort study included patients with endometriosis (n = 50) and a matched control group without endometriosis (n = 150) who delivered singleton term pregnancies at a tertiary center (2008–2023). Maternal characteristics, pregnancy outcomes, and placental histopathology were compared. Results: While maternal and pregnancy characteristics were similar, endometriosis was associated with higher rates of intrapartum fever (10 % vs. 2.6 %, p = 0.045) and placental abnormalities, including placental hemorrhage (10 % vs. 2.6 %, p = 0.045), maternal and fetal inflammatory response features (16 % vs. 6 %, p = 0.039, and 8 % vs. 1.3 %, p = 0.035 respectively), chronic villitis of unknown etiology (8 % vs. 1.3 %, p = 0.035), and chronic deciduitis (14 % vs. 2.6 %, p = 0.006). Composite adverse neonatal outcomes were significantly higher in the endometriosis group (16 % vs. 4 %, p = 0.007). Multivariable regression confirmed associations between endometriosis, inflammatory placental features, and adverse neonatal outcomes. Conclusions: Endometriosis is linked to increased placental inflammatory features and higher adverse neonatal outcome rates. These findings highlight the need for enhanced surveillance and targeted interventions in pregnancies complicated by endometriosis.