Prevalence of preterm birth and risk factors associated with it at different gestational ages

From the Department of Neonatology (Zhang, Zhu Y, Zhu L, Chen, Yuan), Children’s Hospital of Fudan University, from the Division of Neonatology (Lu), Gynecology and Obstetrics Hospital of Fudan University; and from the Key Laboratory of Neonatal Diseases (Chen), National Health Commission, Shanghai, China.

From the Department of Neonatology (Zhang, Zhu Y, Zhu L, Chen, Yuan), Children’s Hospital of Fudan University, from the Division of Neonatology (Lu), Gynecology and Obstetrics Hospital of Fudan University; and from the Key Laboratory of Neonatal Diseases (Chen), National Health Commission, Shanghai, China.

From the Department of Neonatology (Zhang, Zhu Y, Zhu L, Chen, Yuan), Children’s Hospital of Fudan University, from the Division of Neonatology (Lu), Gynecology and Obstetrics Hospital of Fudan University; and from the Key Laboratory of Neonatal Diseases (Chen), National Health Commission, Shanghai, China.

From the Department of Neonatology (Zhang, Zhu Y, Zhu L, Chen, Yuan), Children’s Hospital of Fudan University, from the Division of Neonatology (Lu), Gynecology and Obstetrics Hospital of Fudan University; and from the Key Laboratory of Neonatal Diseases (Chen), National Health Commission, Shanghai, China.

From the Department of Neonatology (Zhang, Zhu Y, Zhu L, Chen, Yuan), Children’s Hospital of Fudan University, from the Division of Neonatology (Lu), Gynecology and Obstetrics Hospital of Fudan University; and from the Key Laboratory of Neonatal Diseases (Chen), National Health Commission, Shanghai, China.

From the Department of Neonatology (Zhang, Zhu Y, Zhu L, Chen, Yuan), Children’s Hospital of Fudan University, from the Division of Neonatology (Lu), Gynecology and Obstetrics Hospital of Fudan University; and from the Key Laboratory of Neonatal Diseases (Chen), National Health Commission, Shanghai, China.