Yang, Yan
Zhou, Li
Zhang, Wenling
Yang, Yanjun
Liu, Yanyan
Pan, Li
Huo, Yanbei
Wang, Ruijuan
Ba, Yupei
Ren, Xiaoyu
Bai, Yana
Cheng, Ning
Article History
Received: 29 April 2022
Accepted: 7 July 2022
First Online: 17 August 2022
Declarations
:
: This is an observational study<i>.</i> The Lanzhou University and Maternal and Child Health Care Hospital of Lanzhou Research Ethics Committee has confirmed that no ethical approval is required.
: The authors affirm that research participants provided informed consent for publication
: The authors declare no competing interests.