1. Division of Reproductive Medicine; Center of Maternal-Fetal, Neonatal, and Reproductive Medicine; National Center for Child Health and Development; Tokyo Japan
2. Department of Obstetrics and Gynecology; Saitama Medical University; Saitama Japan
3. Sora no Mori Clinic; Okinawa Japan
4. Department of Obstetrics and Gynecology; Graduate School of Biomedical Sciences; Tokushima University; Tokushima Japan
5. Department of Comprehensive Reproductive Medicine; Graduate School; Tokyo Medical and Dental University; Tokyo Japan
6. Department of Obstetrics and Gynecology; Tokyo Metropolitan Bokutoh Hospital; Tokyo Japan
7. Department of Obstetrics and Gynecology; Nippon Medical School; Tokyo Japan
8. Japan Medical Association Research Institute; Tokyo Japan
9. Department of Obstetrics and Gynecology; School of Medicine; Keio University; Tokyo Japan