Ma, Zhan-Ying
Deng, Hua
Hua, Li-Dong
Lei, Wen
Zhang, Chang-Bin
Dai, Qi-Qiang
Tao, Wei-Jing
Zhang, Liang https://orcid.org/0000-0003-0782-0688
Article History
Received: 25 July 2019
Accepted: 18 February 2020
First Online: 22 February 2020
Ethics approval and consent to participate
: The study protocol was approved by the Institutional Ethics Board of Dongguan Maternal and Child Health Care Hospital. Written informed consent was obtained from each parent or guardian.
: Not applicable.
: The authors declare that they have no competing interests.