Article History
Received: 16 July 2021
Accepted: 2 October 2021
First Online: 8 November 2021
Declarations
:
: The study was approved by Hangzhou Women’s Hospital (Hangzhou Maternity and Child Health Care Hospital) ethics committee, and the approval number was [2021] Medical Ethics Review A (3)—02. The data used in this study was anonymized before its use. Patients’ consents were not required because this was a retrospective study.
: Not applicable; this was a retrospective study and no individual person’s personal information is included.
: The authors declare no competing interests.