Wen, Wei
Guo, Meng
Peng, Hong-bing
Ma, Li
Article History
Received: 11 September 2018
Accepted: 18 December 2018
First Online: 27 April 2019
Compliance with ethical standards
:
: The study conducted in the Maternal and Child Health Hospital and was approved by the Medical Ethics Committee of the Maternal and Child Health Hospital of Shenzhen, Guangdong province, China.
: None financial benefits have been received or will be received from any party related directly or indirectly to the subject of this article.