Yan, Wei
Xiong, Yun
Yao, Yu
Zhang, Feng-jiang
Yu, Li-na
Article History
Received: 10 January 2019
Accepted: 3 December 2019
First Online: 30 December 2019
Ethics approval and consent to participate
: The study was approved by the ethics committee of Huzhou Maternity & Child Health Care Hospital (Ethical Committee number 201801; Chairperson Ping-ya He). All participants were informed about the study protocol and provided written consent to participate in the study.
: Not applicable.
: The authors declare that they have no competing interests.