Lian, Qiguo
Lou, Chaohua
Zhong, Xiangyang
Zhang, Jiashuai
Tu, Xiaowen
Fang, Yuhang
Yu, Chunyan
Zuo, Xiayun
Article History
Received: 14 July 2022
Accepted: 27 October 2022
First Online: 7 November 2022
Declarations
:
: During the ongoing COVID-19 pandemic, we obtained passive consent from all the parents or guardians and active consent from all the subjects remotely using digital method.The study was reviewed and approved by the institutional ethics board of Shanghai Institute of Planned Parenthood Research (PJ2020-26), and follows the ethical principles of the Declaration of Helsinki 1964.
: Not applicable.
: None declared.