1. Nursing Department, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan.
2. Department of Women's Health Nursing & Midwifery, Tohoku University Graduate School of Medicine, Miyagi, Japan.
3. Department of Nursing, Yamagata Prefectural University of Health Science, Yamagata, Japan.
4. Health Sciences Department of Nursing, Kansai University of International Studies, Hyogo, Japan.