P-329 Endometriosis and adenomyosis in relation to obstetric outcomes: a Dutch population-based cohort study

Abstract Study question What is the prevalence of obstetric/neonatal complications in pregnancies of women with histopathologic confirmed endometriosis, adenomyosis, or both, versus that of the general (Dutch) population? Summary answer Women with endometriosis, adenomyosis or both, showed increased adverse outcomes. There seems to be a specific profile of complications according to disease phenotype. What is known already Endometriosis is a disease characterized by the presence of endometrium-like epithelium and/or stroma outside the uterus. Adenomyosis is an associated condition defined as endometrium-like tissue infiltrating into the myometrium. Recent studies suggest a relationship between endometriosis and adverse pregnancy outcomes, but evidence remains conflicting, especially regarding the potential added effect of adenomyosis. Study design, size, duration This retrospective population-based study used two Dutch national databases (Perined and Palga) to compare obstetric outcomes in women with histopathologic confirmed endometriosis, adenomyosis, or both, to the general Dutch population. We compared obstetric outcomes of 19,418 pregnancies of women with only endometriosis (group EO), 11,724 pregnancies of women with only adenomyosis (group AO) and 1,048 pregnancies of women with both endometriosis and adenomyosis (group EA), with 4,065,165 pregnancies of the general Dutch population. Participants/materials, setting, methods A multivariate regression analysis was conducted to calculate adjusted odds ratios (aORs) with 95% confidence interval (95% CI) for relevant outcomes. Outcomes were corrected for potential confounders (maternal age, parity, ethnicity, year of registered birth, induction of labor, multiple gestation, ethnicity, low socioeconomic status, history of hypertensive disorders, and mode of conception). A p-value of < 0.05 was considered as statistically significant. Main results and the role of chance When corrected for confounders, Groups EO, AO and EA all showed significantly higher prevalence of placental issues (aOR 1.17 (95% 1.09-1.25), aOR 1.21 (95%CI 1.14-1.31, aOR 1.44 (95% CI 1.08-1.92), respectively), caesarean delivery (aOR 2.73 (95% 2.64-2.82), aOR 1.46 (95% CI 1.39-1.54), aOR 2.51 (95% CI 2.19-2.88), respectively), preterm birth (aOR 1.43 (95% 1.37-1.46), aOR 1.26 (95% CI 1.19-1.34), aOR 1.55 (95% CI 1.30-1.86), respectively), and NICU admission (aOR 1.26 (95% CI 1.22-1.30), 1.09 (95% CI 1.04-1.15), aOR 1.26 (1.08-1.47) respectively) versus the general population. Group EO specifically showed increased prevalence of: placental abruption (aOR 2.084 (95% CI 1.62-2.69), foetal distress (aOR 1.09 (95% CI 1.04-1.14), and perinatal death (aOR 1.34 (1.09-1.58). Group AO specifically had a higher prevalence of placental retention (aOR 1.20 (95% CI 1.08-1.34), threatened prematurity (aOR 1.34 (95% CI 1.23-1.47), miscarriage (aOR 1.59 (95% CI 1.53-1.65), preeclampsia (PE) (aOR 1.26 (95% CI 1.16-1.36) and postpartum hemorrhage (PPH) (aOR 1.22 (95% CI 1.14-1.31). Group EA specifically showed higher rates of placenta praevia (aOR 4.14 (95% CI 2.21-7.73) and endometritis (aOR 4.93 (95% CI 2.05-11.88). No significant differences between any of the groups were seen for dysmaturity, failure to progress, instrumental delivery, or spontaneous vaginal delivery, Limitations, reasons for caution We lacked information on the endometriosis stage, and thus could not correlate disease severity with obstetric outcomes. The reliance on histopathological diagnoses could introduce bias towards more severe cases, as surgery is indicated for advanced disease. We could not correct for BMI and smoking as they were not consistently reported. Wider implications of the findings Our findings suggest that women with endometriosis and/or adenomyosis face more obstetric and neonatal complications. Adenomyosis is linked to miscarriage and hypertensive disorders, and endometriosis with placental issues and adverse neonatal outcomes. Further studies need to clarify the relationship between disease severity and pregnancy risks, and assess potential preventative measures. Trial registration number No