1. Department of Obstetrics and Gynecology Fukushima Medical University School of Medicine Fukushima Japan
2. Department of Obstetrics and Gynecology Oita University Oita Japan
3. Department of Obstetrics and Gynecology, Graduate School of Medical Science Kyoto Prefectural University of Medicine Kyoto Japan
4. Department of Gynecology and Obstetrics Kyoto University Kyoto Japan