Risk of peripartum cerebrovascular events in women with moyamoya disease: A multicenter cohort study

Background: Pregnancy and delivery are known to increase the risk of cerebrovascular events (CVEs) in patients with moyamoya disease (MMD). This study determined the frequency, risk factors, and outcome of CVEs during pregnancy in MMD. Methods: We conducted a multicenter study involving 171 MMD patients with 196 deliveries across four Korean tertiary institutions between 1990 and 2023. Data on MMD-related clinical, imaging, and operative findings were collected. We analyzed CVEs and pregnancy outcomes, including delivery mode and anesthesia. Univariate and multivariate analyses were performed to identify risk factors for peripartum CVEs. Results: Peripartum CVEs occurred in 5.6% of pregnancies, with intracerebral hemorrhage being the most common, followed by cerebral infarction. CVEs were more common in women diagnosed with MMD during pregnancy (85.7% vs. 2.6% in women diagnosed before pregnancy) and in women who had not completed revascularization before pregnancy or were hemodynamically unstable: 55.6% versus 1.1%. Delivery mode and anesthesia showed no significant association with the occurrence of CVEs. Multivariate analysis revealed that the “non-revascularized or hemodynamically unstable” group remained a significant risk factor for peripartum CVEs (adjusted odds ratio (OR) = 353.23, P < 0.001). CVEs resulted in maternal functional impairment in 4 of 11 affected cases (36.4%) and fetal loss in 2 of 11 cases (18.2%). Conclusion: This study highlights the protective effect of revascularization on peripartum CVEs and proposes a structured clinical protocol, recommending prepregnancy hemodynamic assessment and neurosurgical consultation. Women diagnosed with MMD during pregnancy and those in the “non-revascularized or hemodynamically unstable” group should be considered a high-risk group for peripartum CVEs.