Hu, Wenling
Hu, Huanqing
Zhao, Wei
Huang, Aiqun
Yang, Qi
Di, Jiangli
Article History
Received: 29 January 2021
Accepted: 26 May 2021
First Online: 14 June 2021
Declarations
:
: The study was conducted in accordance with the Declaration of Helsinki and was undertaken following all relevant guidelines and regulations. The study was approved and exempt from informed consent by the Ethics Committee for Human Subjects Studies of the National Center for Women and Children’s Health, Chinese Center for Disease Control and Prevention (FY2015–007). The informed consent forms were waived because that all the information in the study was collected from Maternal and Child Care Handbook written by doctors in place of collecting data face-to-face with the objects, and the data we used was lack of identification of individuals.
: Not applicable.
: The authors declare that they have no competing interests.