1. Department of Obstetrics and Gynecology, Akiyama Memorial Hospital
2. Perinatal and Neonatal Medical Center, Aichi Medical University School of Medicine
3. Endowment Department of Mibyou Science and Medicine of Salutogenesis, Health Science Clinic, Osaka Medical College
4. Department of Obstetrics and Gynecology, Hakodate Goryoukaku Hospital
5. Department of Obstetrics and Gynecology, Sapporo Medical University, School of Medicine