1. Department of Obstetrics and Gynecology; Saitama Medical University; Saitama Japan
2. Department of Obstetrics and Gynecology, Graduate School of Biomedical Sciences; Tokushima University; Tokushima Japan
3. Department of Comprehensive Reproductive Medicine, Graduate School; Tokyo Medical and Dental University; Tokyo Japan
4. Department of Obstetrics and Gynecology; Tokyo Metropolitan Bokutoh Hospital; Tokyo Japan
5. Department of Obstetrics and Gynecology, Nippon Medical School; Tokyo Japan
6. Japan Medical Association Research Institute; Tokyo Japan
7. Department of Obstetrics and Gynecology, School of Medicine; Keio University; Tokyo Japan
8. Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine; National Center for Child Health and Development; Tokyo Japan