1. Khon Kaen University; Department of Biostatistics and Demography, Faculty of Public Health; Khon Kaen Thailand 40002
2. Khon Kaen University; Department of Obstetrics and Gynaecology, Faculty of Medicine; 123 Mitraparb Road Amphur Muang Khon Kaen Thailand 40002
3. Christchurch Polytechnic Institute of Technology; School of Midwifery, Faculty of Health Sciences; 3 Henridge Place Avonhead Christchurch Canterbury New Zealand 8042
4. Faculty of Medicine, Khon Kaen University; Department of Otolaryngology; 123 Friendship Road Amphur Muang Khon Kaen Thailand 40002
5. Khon Kaen University; Department of Adult Nursing, Faculty of Nuring; Faculty of Nursing Muang District Khon Kaen Thailand 40002