1. Institute of Environmental and Gender-specific Medicine, Juntendo University Graduate School of Medicine, Chiba, Japan
2. Department of Obstetrics & Gynecology, Juntendo University Graduate School of Medicine, Tokyo, Japan
3. Division of Microbiology and Immunology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan
4. Department of Obstetrics & Gynecology, Kanazawa University Graduate School of Medical Sciences, Ishikawa, Japan