As moyamoya disease in pregnancy is clinically rare, it is poorly understood. We therefore analyzed our experiences of moyamoya disease pregnancies and deliveries over three decades.

The clinical data of 78 pregnancies and 77 deliveries among 62 moyamoya disease cases at Tokyo Medical and Dental University Hospital from 1991 to 2019 were retrospectively reviewed.

There were six, 17 and 55 pregnancies in the first, second, and last decades, respectively. The mean patient age at delivery was 29.3 ± 5.0 years. The primary symptoms of moyamoya disease at diagnosis were ischemia in 50 cases (64.1%) and intracranial hemorrhage in eight cases (10.2%). Cesarean section was performed in 75 cases (96.2%). Fifteen pregnancies (19.2%) developed hypertensive disorders of pregnancy; of these, 13 (86.7%) developed hypertensive disorders of pregnancy after 34 weeks of gestation and 9 (60%) required emergency cesarean section because of a sudden increase in blood pressure. Four (5.1%) women experienced renal artery stenosis complications and three of them developed hypertension during pregnancy. Two (2.6%) experienced cerebral infarctions several days after delivery, both of whom had no subsequent aftereffects. No cases of hemorrhagic stroke were reported in the peripartum period.

To date, this is the largest single-center analysis. It showed the number of moyamoya disease pregnancies has risen rapidly over the last decade. The hypertensive disorders of pregnancy and emergency cesarean section rates were high among moyamoya disease patients. Minor ischemic stroke was observed, but its prevalence was low. Therefore, pregnant women with moyamoya disease should be managed with the understanding that hypertensive disorders of pregnancy is a common complication.