Natural History and Risk Factors for Adverse Outcomes of Ovarian Endometrioma in Pregnancy - A 9-Year Cohort with Histopathological Confirmation

Purpose

This study aimed to characterize the natural history of ovarian endometrioma (OE) during pregnancy and identify independent risk factors for adverse outcomes. Patients and methods: This retrospective cohort study was conducted at Hangzhou Women's Hospital and included 151 patients with OE histopathologically confirmed during cesarean section between January 2017 and December 2025. Patients were stratified according to the timing of OE detection: Group 1 (n = 86; OE detected before conception or before 14 weeks of gestation) and Group 2 (n = 65; OE first identified intraoperatively during cesarean section). The serial cyst dimensions in Group 1 were reviewed to assess gestational changes in cyst size during pregnancy. Composite adverse outcomes included cyst rupture, suspected malignant transformation, or cyst-related iatrogenic preterm birth. Risk factors were evaluated using univariable and multivariable logistic regression analyses.