1. Department of Obstetrics and GynecologyUniversity of Toyama Toyama Japan
2. Department of Obstetrics and GynecologyTonami General Hospital Tonami Toyama Japan
3. Department of Obstetrics and GynecologyNippon Medical School Bunkyo City Tokyo Japan
4. Laboratory for Recurrent Pregnancy LossSugi Women's Clinic Yokohama Kanagawa Japan
5. Department of Obstetrics and GynecologyUniversity of Tokyo Bunkyo City Tokyo Japan
6. Department of Obstetrics and GynecologyKobe University Graduate School of Medicine Kobe Hyogo Japan
7. Graduate School of Health SciencesOkayama University Okayama Japan
8. Department of Obstetrics and GynecologyHyogo College of Medicine Nishinomiya Hyogo Japan