Zhang, Le
Xu, Chengjie
Li, Yue
Article History
Received: 18 April 2021
Accepted: 1 September 2021
First Online: 22 September 2021
Declarations
:
: Ethical approval was given by the institutional ethics committee (IRB of the Obstetrics and Gynecology Hospital of Fudan University) and registered at Clinical Research Information Service with registration number ChiCTR2100045162. Informed consent of information collection for research was obtained from all participants. All methods in this retrospective study were carried out in accordance with institutional guildlines and regulations. The study was performed in accordance with the ethical standards of the Declaration of Helsinki (1964) and its subsequent amendments.
: Informed consent of information collection for research was obtained from all participants. And the institutional review board provided us the consent to publish.
: We have no competing interests.