Zhao, Jing
Chen, Daye
Article History
Received: 5 November 2019
Revised: 28 May 2020
Accepted: 5 June 2020
First Online: 20 July 2020
Competing interests
: The authors declare no competing interests.
: This study was conducted with the ethical approval from the Ethics Committee of the Yancheng Maternal and Child Health Care Hospital (approval number: KY2019032) and the written informed consents of all participants.
: This study was conducted with the written informed consents of all participants.