Sichuan University, Sichuan University - West China Second University Hospital, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University - National Office for Maternal and Child Health Surveillance of China, Sichuan University, Southern Medical University and Sichuan University - National Office for Maternal and Child Health Surveillance of China