Article History
Received: 30 June 2023
Accepted: 6 September 2023
First Online: 13 October 2023
Declarations
:
: The authors declare that they have no competing interests.
: The requirement of ethical approval for this was waived by the Institutional Review Board of Nantong Maternal and Child Health Care Hospital, because the data was accessed from NVSS (a publicly available database).
: Not applicable.
: The need for written informed consent was waived by the Institutional Review Board of Nantong Maternal and Child Health Care Hospital due to retrospective nature of the study.