1. Prince of Songkla University; Epidemiology Unit, Faculty of Medicine; Hat Yai Songkhla Thailand 90110
2. Prince of Songkla University; Department of Obstetrics and Gynecology, Faculty of Medicine; Hat Yai Songkhla Thailand 90110
3. World Health Organization; Department of Family, Health and Research; Regional Office for South-East Asia World Health House, Indraprastha Estate Mahatma Gandhi Marg New Delhi India 110 002