Funding for this research was provided by:
Fujian Maternity and Child Health Hospital (No.YCXB 18-10 and YCXM 19-04)
Article History
Received: 17 April 2020
Accepted: 22 June 2020
First Online: 27 June 2020
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.