1. Department of Obstetrics and Gynecology Kurume University School of Medicine Fukuoka Japan
2. Center for Perinatal Medicine JCHO Sagamino Hospital Kanagawa Japan
3. Department of Gynecology Tokyo Kyosai Hospital Tokyo Japan
4. Department of Obstetrics and Gynecology Tohoku University School of Medicine Miyagi Japan
5. Department of Obstetrics and Gynecology Nippon Medical School Tokyo Japan
6. Department of Obstetrics and Gynecology Osaka University School of Medicine Osaka Japan