Sun, Xiaotong
Qu, Tao
He, Xiyan
Yang, Xueping
Guo, Nan
Mao, Yan
Xu, Xianghong
Sun, Xiaodong
Zhang, Xuehong
Wang, Weihua
Funding for this research was provided by:
Gansu Provincial Commission of Health and Family Planning (GSWSKY2016-48)
Gansu Provincial Hospital (17GSSY2-3, 16GSSY4-4)
Lanzhou science and technology program (2017-4-68)
Article History
Received: 3 August 2018
Accepted: 19 October 2018
First Online: 7 November 2018
Ethics approval and consent to participate
: The study was approved by the Ethical Committee of the Gansu Provincial Hospital. All study participants agreed to the sample collection and provided written informed consent.
: All mothers provided written informed consent to publish their individual information.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.