1. Department of Obstetrics and Gynecology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan
2. Department of Maternal Fetal Medicine, Center for Maternal, Fetal and Neonatal Medicine, Shikoku Medical Center for Children and Adults, 2-1-1 Zentsuji, Kagawa 765-8507, Japan