1. Khon Kaen University; Department of Obstetrics and Gynaecology, Faculty of Medicine; 123 Mitraparb Road Amphur Muang Khon Kaen Thailand 40002
2. Faculty of Medicine; Department of Obstetrics & Gynaecology; Khon Kaen University Khon Kaen Thailand
3. Khon Kaen University; Department of Biostatistics and Demography, Faculty of Public Health; 123 Mitraparb Road Amphur Muang Khon Kaen Thailand 40002