Risk of First Hemorrhage of Brain Arteriovenous Malformations During Pregnancy: A Systematic Review of the Literature.

Recommendations on the management of brain arteriovenous malformations (bAVM) with respect to pregnancy are based upon conflicting literature.To systematically review the reported risk and annualized rate of first intracranial hemorrhage (ICH) from bAVM during pregnancy and puerperium.MEDLINE, EMBASE, and Scopus databases were searched for relevant articles in English published before April 2018. Studies providing a quantitative risk of ICH in bAVM during pregnancy were eligible.From 7 initially eligible studies, 3 studies met the criteria for providing quantitative risk of first ICH bAVM during pregnancy. Data from 47 bAVM ICH during pregnancy across 4 cohorts were extracted for analysis. Due to differences in methodology and definitions of exposure period, it was not appropriate to combine the cases. The annualized risk of first ICH during pregnancy for these 4 cohorts was 3.0% (95% confidence interval [CI]: 1.7-5.2%); 3.5% (95% CI: 2.4-4.5%); 8.6% (95% CI: 1.8-25%); and 30% (95% CI: 18-49%). Only the last result from the last cohort could be considered significantly increased in comparison with the nonpregnant period (relative rate 6.8, 95% CI: 3.6-13). The limited number of eligible studies and variability in results highlighted the need for enhanced rigor of future research.There is no conclusive evidence of an increased risk of first hemorrhage during pregnancy from bAVM. Because advice to women with bAVM may influence the management of pregnancy or bAVM with significant consequences, we believe that a retrospective multicenter, case crossover study is urgently required.