1. Khon Kaen University; Department of Obstetrics and Gynaecology, Faculty of Medicine; 123 Mitraparb Road Amphur Muang Khon Kaen Thailand 40002
2. Khon Kaen University; Department of Epidemiology and Biostatistics, Faculty of Public Health; 123 Mittraphap Rd. Nai-Muang Muang District Khon Kaen Thailand 40002
3. Khon Kaen University; Cochrane Thailand; Khon Kaen Thailand
4. Faculty of Medicine, Chiang Mai University; Department of Obstetrics and Gynecology; 110 Intawaroros Road Muang Chiang Mai Thailand 50200