Pregnancy and Delivery and Moyamoya Disease Delivery Most important issue related to pregnancy in moyamoya disease is the way of delivery: Which is safer between vaginal (spontaneous) and caesarian section? Hyperventilation at delivery and hypertension caused by pain may cause problems for the pregnant women with moyamoya disease. From the data in the literature, there has been no major problem when moyamoya disease had been diagnosed before the patients become pregnant. However, many neurosurgeons believe that spontaneous delivery has more potential risk than caesarian section without supporting data. To avoid problems at delivery, scheduled caesarian section is preferred in Japan for fear of possible court problems. Apparent advantages of caesarian section may be as follows: caesarian section is the scheduled procedure in the daytime when many personnel are in the hospital and in case of emergency, better medical resource is available. It is better to deliver in the center hospital where neurosurgeons, anesthesiologists, and obstetricians are available. In the medical literature, one case report recommends the provocative hyperventilation challenge in the late pregnancy to evaluate the risk of vaginal delivery using cerebral blood flow measurement. I believe that this kind of examination can do harm the patient, but can not provide any useful information on the risk of vaginal delivery. Anesthesia There is no consensus on the safe method of anesthesia for the delivery of moyamoya patient. In the literature, general anesthesia (inhalation or intravenous), spinal anesthesia, and epidural anesthesia have been reported. Each method has its own merits and demerits. General anesthesia may provide stable systemic condition, but hypertension, vomiting at intubation of the tracheal tube, and sleeping baby after delivery are drawbacks. Spinal and epidural anesthesia may cause hypotension, and the patient may present hyperventilation or hypertension due to anxiety. Epidural anesthesia can provide good pain control in the post-delivery period. As discussed above, there has been no established safest method of delivery, anesthesia, but it may be the best method, with which obstetricians, anesthesiologists and neonatologists are familiar. Not only the methodology, but the medical personnel' system in each hospital should be taken account for. References 1. Komiyama M, Yasui T, Kitano S, Sakamoto H, Fujitani K, Matsuo S: Moyamoya disease and pregnancy: case report and review of the literature. Neurosurgery 43: 360-369, 1998 [abstract] 2. Komiyama M: Moyamoya disease and pregnancy. (letter). J Nucl Med 40: 214-215, 1999