Funding for this research was provided by:
Talent Project of Provincial Science and Technology Deparment (BRA2019160)
Major Project of Changzhou Commission of Health (ZD201922)
Jiangsu natural science foundation general project (BK20191159)
Received: 8 January 2020
Accepted: 12 May 2020
First Online: 20 May 2020
Ethics approval and consent to participate
: Informed consent was obtained from each participant. The study design and protocol were reviewed and approved by the ethics committee of Changzhou Maternity and Child Health Care Hospital affiliated to Nanjing Medical University (Approval No:CZFY20160103).
: Not applicable.
: The authors declare that they have no competing interests.