Clinical data on pregnancy in association with moyamoya disease There have been 68 cases in the medical literature. Those who diagnosed to have moyamoya disease in childhood, who grow up and become pregnant. There are 37 patients. Twenty eight patients underwent Caesarian section and nine patients spontaneous (vaginal) delivery. Only one patient had poor prognosis, who had been diagnosed to have moyamoya disease at the age of 10. This patient developed bilateral ventricular hemorrhage. Although the baby was healthy, the patient was in the state of akinetic mutism. Another patient developed hypertension and hyperventilation during Caesarian section under spinal anesthesia due to probably anxiety. There was no adverse effect to both the patient and the baby. There was no clinical problem in 36 patients. Surprisingly, only nine patients underwent at least unilateral bypass surgery. Those who developed stroke during pregnancy, who are diagnosed to have moyamoya disease for the first time There are 31 patients. Twenty patients underwent Caesarian section, six vaginal delivery, two abortions and three unknown. Clinical ictus occurred during the course of pregnancy in 24, during delivery in three, after childbirth in three, and one unknown. Hemorrhage occurred in 24, ischaemia in six, and one unknown. Prognosis of the mother was good in 15, poor in five, unknown in two. Prognosis of the baby was good in 22, poor in one and death in three (including two abortions). Among 31 patients, toxemia was apparent in three. Most of the patient were primipara and seven were secundipara or more. From the data "Clinical investigation on MOYAMOYA DISEASE" (2001) Data on 87 female moyamoya patients above the age of 18 years old No history of delivery (20 patients), in pregnancy (1 patient), delivery after the diagnosis of moyamoya disease (22 patients), delivery before the diagnosis of moyamoya disease (27 patients), diagnosis made after the delivery of the first child (2 patients), diagnosis made after the delivery of the second child (9 patients), diagnosis made after the delivery of the third child (4 patients), diagnosis made after the delivery of the fourth child (1 patient), diagnosis made after delivery (1 patient), and diagnosis made during pregnancy (1 patient). Delivery after the diagnosis of moyamoya disease (20 patients) Spontaneous delivery (7 patients), caesarian section (11 patients), and painless delivery (1 patient). Complication during pregnancy (delivery) (49 patients) No complication (35 patients), complicated pregnancy (delivery) (13 patients), and unknown (1 patient). Complications included toxemia and hypertension, and less frequently the increase of ischaemia episodes. It is not clearly stated that how many patients were diagnosed for the first time during pregnancy and how many complications during pregnancy (delivery) either before or after the diagnosis of moyamoya disease.