Moyamoya ("hazy puff-of-smoke") disease represents a rare condition with progressive narrowing and occlusion of basal cranial vessels with secondary specific neoangiogenesis; we report on a 25-year-old primigravida with known moyamoya disease who suffered from acute bilateral intraventricular haemorrhage at 24 weeks gestation. She underwent bilateral external ventricular drainage and intraventricular recombinant tissue plasminogen activator (r-TPA) lysis was performed. At 34 weeks' gestation, a healthy girl was delivered via Caesarean section. Encephalomyosynangiosis (EMS) and extra-intracranial (EC/IC) bypass surgery were performed six and eight months after delivery, respectively. The patient recovered almost completely and showed only mild residual deficits. Prompt diagnosis and immediate interdisciplinary treatment might have been the key for optimal maternal and neonatal outcome in our patient.