1. Department of Neonatology West China Second University Hospital Sichuan University Chengdu P.R. China
2. Department of Nursing West China Second University Hospital Sichuan University Chengdu P.R. China
3. Key Laboratory of Birth Defects and Related Diseases of Women and Children Ministry of Education Chengdu P.R. China
4. West China School of Nursing Sichuan University Chengdu P.R. China
5. National Center for Women and Children's Health Chinese Center for Disease Control and Prevention Beijing P.R. China
6. Department of Neonatology, Faculty of Pediatrics Chinese PLA General Hospital Beijing P.R. China