1. Department of Obstetrics and Gynecology Nippon Medical School Tokyo Japan
2. Department of Obstetrics and Gynecology Chiba Hokusoh Hospital, Nippon Medical School Chiba Japan
3. Department of Microbiology and Immunology Nippon Medical School Tokyo Japan
4. Department of Obstetrics and Gynecology Kawaguchi Municipal Medical Center Saitama Japan
5. Department of Obstetrics and Gynecology Nihon University School of Medicine Tokyo Japan