Guo, Fei
Yang, Shuai
Zhang, Yong
Yang, Xi
Zhang, Chen
Fan, Jianxia http://orcid.org/0000-0003-3338-877X
Funding for this research was provided by:
the Shanghai Municipal Commissions of Health and Family Planning Program (15GWZK0701)
Article History
Received: 2 October 2019
Accepted: 24 December 2019
First Online: 20 January 2020
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of the International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University (no. GKLW2012–49). The data analysis procedures conformed to the guidelines in the Declaration of Helsinki. All participants provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.