Zhao, Ping
Li, Ting
Wang, Youliang
Wang, Yong
Gu, Qi
Li, Zhi
Article History
Received: 27 November 2020
Accepted: 5 April 2021
First Online: 19 April 2021
Declarations
:
: This study was approved by Gansu Provincial Maternity and Childcare Hospital and all the patients or their parents/guardians provided written informed consent.
: The authors declare no competing interests.