Institution: | 1. National Center for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Chengdu, 610041, China;2. Pediatric Department, West China Second University Hospital, Sichuan University, Chengdu, 610041, China;3. Obstetric and Gynecologic Department, West China Second University Hospital, Sichuan University, Chengdu, 610041, China;4. Yale University School of Public Health, New Haven, Connecticut |