[1] Univ Kebangsaan Malaysia, Fac Med, Dept Publ Hlth Med, Kuala Lumpur 56000, Malaysia
[2] Minist Hlth, Family Hlth Dev Div, Complex E, Putrajaya 62590, Malaysia
[3] Univ Kebangsaan Malaysia, Fac Med, Dept Obstet & Gynaecol, Kuala Lumpur 56000, Malaysia