Li, Xiao
Liu, Meihua
Ji, Yurou
Qu, Pengpeng
Article History
Received: 18 February 2021
Accepted: 4 May 2021
First Online: 12 May 2021
Declarations
:
: This study was approved by the Ethics Committee of Tianjin Central Hospital of Gynecology and Obstetrics. The requirement for informed consent was waived due to the retrospective study design.
: Not applicable.
: The authors declare no competing interests.