1. Department of Obstetrics and Gynaecology, Faculty of Medicine and Health Sciences , Universiti Putra Malaysia , 43400 UPM Serdang , Selangor , Malaysia
2. Department of Obstetrics and Gynaecology , Universiti Kebangsaan Malaysia Medical Centre , Kuala Lumpur , Malaysia
3. Department of Community Health , Universiti Kebangsaan Malaysia Medical Centre , Kuala Lumpur , Malaysia