1. Department of Women, Children and Family Planning Information, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
2. International Center for Reproductive Health, Department of Public Health and Primary Care, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
3. Epidemiology, Biostatistics and Clinical Research Center, School of Public Health, Université Libre de Bruxelles (ULB), Bruxelles, Belgium
4. Department of Hematology, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, China