You Sub Kim, Sung Pil Joo, Tae Sun Kim
Background: Aneurysmal subarachnoid hemorrhage (SAH) during pregnancy is rare, occurring in approximately 0.01–0.05% of pregnancies, most commonly in the third trimester. Its management is particularly challenging, requiring careful consideration of both maternal and fetal outcomes. Methods: We report the case of a 32-year-old woman at 31 weeks of gestation who presented with severe headache and left third cranial nerve palsy. Imaging revealed diffuse SAH with significant obstructive hydrocephalus and a 5 mm left posterior communicating artery aneurysm. Following multidisciplinary discussion, surgical clipping was performed while preserving the pregnancy to allow for fetal lung maturation. On postoperative day 8, the patient developed right-sided weakness and aphasia secondary to severe vasospasm. Initial management with catecholamine-induced hypertension resulted in increased uterine contractions and fetal distress. Subsequent intra-arterial administration of nimodipine effectively resolved the vasospasm, enabling cessation of vasopressor therapy. After achieving fetal lung maturity, cesarean section was performed at 34 weeks, followed by ventriculo-peritoneal shunt placement for communicating hydrocephalus. Due to sustained shunt failure, the distal catheter was finally inserted into the superior vena cava at the junction of the atrium. Results: The patient showed gradual neurological recovery with complete resolution of third cranial nerve palsy, and both mother and infant were discharged without complications. Conclusions: This case highlights that while standard vasospasm therapies can be implemented during pregnancy, hemodynamic approaches may provoke maternal and fetal complications. Endovascular rescue strategies should be promptly considered for severe vasospasm, and ventriculo-atrial shunting for complex communicating hydrocephalus may serve as a viable alternative option in post-cesarean patients.