Introduction Brain arteriovenous malformations (AVM) account for a significant percentage of brain hemorrhages in pregnant patients. There is general consensus that ruptured AVMs in pregnant women should be managed based on neurosurgical rather than obstetric considerations. Since the risk of re-hemorrhage is significantly higher in the pregnant patient with a ruptured AVM, aggressive treatment during pregnancy must be considered if this can be accomplished with acceptable risk. Recent advances in endovascular technology have increased the potential for successful treatment of previously inoperable high-grade AVMs.

Case report A 17-year-old woman pregnant with twins experienced sudden onset headache and became unresponsive at 20 weeks gestation. A CT scan of the head showed cerebellar hemorrhage and obstructive hydrocephalus. Cerebral angiography showed a 5.5 cm AVM in the cerebellar vermis with deep drainage for a Spetzler Martin grade IV classification. Extensive two-stage Onyx embolization with complete casting of the nidus was performed. The patient delivered healthy twin girls at 36 weeks gestation by a planned cesarean section. This was followed by surgical resection of the AVM 4 months later with minimal blood loss. A follow-up angiogram showed no evidence of AVM recurrence 3 months after surgical resection. Her balance was significantly improved and she walked unassisted. She had mild cerebellar speech. Her twin girls are progressing normally.

Conclusion Extensive endovascular Onyx embolization is feasible in the setting of a ruptured high-grade AVM during pregnancy. The rationale for proceeding with treatment is the perceived higher likelihood of re-hemorrhage from such a lesion.