Jing, Liu
Dan, Zheng
Huiqun, Wang
Yanping, Liu
Yang, Lu
Xuan, Yin
Mengmou, Zheng
Didong, Lou http://orcid.org/0000-0003-0059-1587
Article History
Received: 23 January 2020
Accepted: 13 June 2020
First Online: 28 July 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: The study protocol was approved by the ethics committee of Guiyang Maternal and Child Health Hospital.
: Informed consent was obtained from women who participated.