Ma, Ning
Bai, Liwei
Niu, Ziru
Lu, Qiang
Article History
Received: 8 March 2024
Accepted: 28 June 2024
First Online: 4 July 2024
Declarations
:
: The present trial followed the Declaration of Helsinki (2000) and had approval from the Ethics committee of Qinhuangdao Hospital for Maternal and Child Health [2021Q088]. The requirement for informed consent was waived by the Institutional Review Board of Ethics committee of Qinhuangdao Hospital for Maternal and Child Health because of the retrospective nature of the study.
: Not applicable.
: The authors declare no competing interests.