Pregnancy and Delivery in Female Moyamoya Patients Moyamoya disease is more prevalent in women than men. Many female patients develop the disease in childhood. This means that many of them face the problems in pregnancy and delivery when they grow up. Unfortunately, there has been no guideline for them and the physicians involved are at puzzle when they are consulted by the female patients. Although many female moyamoya patients delivery without problems in fact, there are clinical issues regarding their pregnancy. When we discuss the clinical issues in pregnancy of female moyamoya patients, two groups should be discriminated because of differences in clinical picture: the patients who have been diagnosed before pregnancy and the patients who are diagnosed for the first time during pregnancy. Moyamoya disease diagnosed before pregnancy Contraception: Contraceptive pills are known as a risk factor of brain infarction. It is better to avoid their usage for contraception. Delivery: It is an unsolved issue whether caesarian section is safer than spontaneous vaginal delivery. From the limited data in the literature, there is no evidence that spontaneous delivery carries more risk. However, since malpractice is the current social concern, caesarian section is frequently chosen for fear of court problems. Sterile treatment: In the course of treatment, hormone drug is used, which are regarded to have a risk of brain ischemia similar to contraceptive pills. Moyamoya disease diagnosed for the first time during pregnancy Most patients develop brain hemorrhage. Some are so serious and life-threatening, and some are not. Treatment is directed to the mother first to treat brain hemorrhage. When the caesarian section is possible for the baby, caesarian section is attempted. In general, treatment of pregnant women (non-moyamoya patients) are basically the same to that for the non-pregnant women. Except for the early stage of pregnancy, x-ray exposure, drug administration, and surgery do not cause adverse effects to the baby.