Abstract DP359: Pregnancy and Risk of Subarachnoid Hemorrhage in Young Patients with Unruptured Cerebral Aneurysm Diagnosis

Introduction: Pregnancy-related physiological changes may influence the risk of aneurysmal rupture, raising concerns for young patients with known unruptured cerebral aneurysms. This study aims to evaluate the relationship between pregnancy and the risk of subarachnoid hemorrhage (SAH) in young female patients. Methods: We conducted a retrospective study using the COSMOS EPIC database. Female patients aged 18–50 years with a diagnosis of unruptured cerebral aneurysm (ICD-10 M-code: I67.1) were included. Pregnancy was defined as the presence of any pregnancy-related ICD-10 code. The cohort was divided into two groups based on pregnancy status, and propensity score weighting (PSW) was applied to balance baseline characteristics. The association between pregnancy and SAH was evaluated using a Cox adjusted model. Results: A total of 35,346 patients were included, of whom 6,532 (18%) had a pregnancy-related ICD-10 code. Pregnant patients were younger (mean age 34.23 vs. 40.78 years; p = 0.001) and more likely to be Black (22.3% vs. 17%; p = 0.001). They were less likely to have diabetes, hyperlipidemia, or hypertension. After PSW, baseline characteristics were balanced between the groups. The incidence of SAH was similar (2.3% vs. 2.1%), with no statistically significant difference. Pregnancy was not associated with an increased risk of SAH in the Cox adjusted model (HR 1.11, 95% CI 0.91–1.34). Conclusion: In this large, retrospective cohort of young women with unruptured cerebral aneurysms, pregnancy was not associated with a significantly increased risk of SAH. These findings suggest that pregnancy may not independently elevate aneurysm rupture risk, though individualized risk assessment remains important.