1. Division of Birth Cohort Study; Guangzhou Women and Children's Medical Center; Guangzhou Medical University; Guangzhou China
2. Nuffield Department of Population Health; University of Oxford; Oxford UK
3. Department of Woman and Child Health Care; Guangzhou Women and Children's Medical Center; Guangzhou Medical University; Guangzhou China
4. Department of Obstetrics and Gynecology; Guangzhou Women and Children's Medical Center; Guangzhou Medical University; Guangzhou China
5. Department of Neonatal Surgery; Guangzhou Women and Children's Medical Center; Guangzhou Medical University; Guangzhou China
6. Nuffield Department of Women's and Reproductive Health; University of Oxford; Oxford UK