1. Department of Perinatology and Gynecology, National Cerebral and Cardiovascular Center, Suita, Japan
2. Department of Obstetrics and Gynecology, Sakakibara Heart Institute, Tokyo, Japan
3. Department of Cerebrovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
4. Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan
5. Department of Obstetrics and Gynecology, Mie University, Mie, Japan