1. General Center for Perinatal, Maternal and Neonatal Medicine, Niigata University Medical and Dental Hospital, Niigata 951-8520, Japan
2. Department of Pediatrics, Akita University Graduate School of Medicine, Akita 010-8543, Japan
3. Global Health Nursing, Graduate School of Nursing Science, St. Luke’s International University, Chuo-ku, Tokyo 104-0044, Japan
4. Tokyo Foundation for Policy Research, Minato-ku, Tokyo 106-0032, Japan
5. Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Saitama 350-8550, Japan