1. Department of Midwifery and Women’s Health, Division of Health Sciences and Nursing, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
2. Global Nursing Research Center, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
3. Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
4. Department of International Health Care and Midwifery, Graduate School of Nursing, Japanese Red Cross College of Nursing, Tokyo 150-0012, Japan
5. Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo 113-0033, Japan
6. Department of Clinical Nursing, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan
7. Department of Reproductive Health Nursing, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
8. Department of Children and Women’s Health, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan