Wan, Sheng
Yang, Mengnan
Pei, Jindan
Zhao, Xiaobo
Zhou, Chenchen
Wu, Yuelin
Sun, Qianqian
Wu, Guizhu
Hua, Xiaolin http://orcid.org/0000-0003-1098-5010
Article History
Received: 25 May 2021
Accepted: 20 January 2022
First Online: 1 February 2022
Declarations
:
: This study was approved by the Ethics Review Committee of Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine (reference number: KS20268). We declare that all methods of this study were performed in accordance with the relevant guidelines and regulations (Declaration of Helsinki). Permission to access charts of mothers for retrieving data obtained from Shanghai First Maternity and Infant Hospital. Because the study was a retrospective chart review, the Ethics Review Committee of Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine has waived the requirement of the informed consent for this study. However, confidentiality was maintained when handling each case files.
: Not required.
: The authors declare that they have no competing interests.