1. Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand
2. Department of Obstetrics and Gynaecology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
3. Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan
4. UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, WHO, Geneva, Switzerland