Pregnancy and delivery in moyamoya disease: results of a nationwide survey in Japan.

Stroke during pregnancy associated with moyamoya disease (MMD) has been reported sporadically, but no systematic surveys have been undertaken. To reveal the current clinical situation, the authors conducted Japan's first nationwide survey of pregnancy and delivery associated with MMD. A questionnaire was sent to all 270 perinatal medical centers across Japan to survey their experiences with delivery associated with MMD within the preceding 5 years (Survey I); another questionnaire was sent to 554 adult female patients with MMD regarding their experience with childbirth (Survey II). Survey I included 59 deliveries among patients with previously diagnosed MMD. The incidence of perinatal neurological events and morbidity was 5.1% and 1.7%, respectively. In another five cases, newly diagnosed after perinatal attacks, disability was noted in three cases, including one death from intracranial hemorrhage. Survey II included 278 deliveries. The perinatal attack rate was 6.6% in 76 previously diagnosed cases and 2.0% in 202 cases undiagnosed at pregnancy, but neither group reported permanent morbidity. Caesarean section in previously diagnosed cases accounted for 76.3% of deliveries in Survey I and 69.7% in Survey II, but no significant difference in event rate was found between caesarean section and vaginal delivery in either survey. Although the incidence of perinatal neurological events is low when MMD has been diagnosed, careful monitoring is required in light of the potential for stroke. Serious events, especially intracranial hemorrhage, can occur if MMD has not been diagnosed at pregnancy. Further efforts to establish management guidelines are required to ensure safer childbirth in patients with MMD.