1. Specialized Diagnostic Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health Malaysia, Kuala Lumpur 50588, Malaysia
2. Institute for Health Management, National Institutes of Health, Ministry of Health Malaysia, Shah Alam 40170, Malaysia
3. Department of Obstetrics and Gynecology, Hospital Tuanku Fauziah, Ministry of Health Malaysia, Kangar 01000, Malaysia
4. Kedah State Health Department, Ministry of Health Malaysia, Alor Setar 05400, Malaysia