[1]Department of Pediatrics Huazhong University of Science and Technology Hospital Wuhan 430074 China;
[2]Neonatal Intensive Care Unit Hubei Maternity and Children''''s Hospital Wuhan 430070 China;
[3]Department of Pediatrics Union Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430022 China;
[4]Department of Urology Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China;
corticosteroid; pulmonary surfactant; preterm infants; bronchopulmonary dysplasia; neonatal respiratory distress syndrome; meta-analysis;