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