1. National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, P.R. China
2. The Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
3. Department of Gynecology, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, P.R. China
4. Department of Neurosurgery, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, P.R. China