Funding for this research was provided by:
the Natural Science Fund of the Jiangsu Higher Education Institutions (No. 17KJB310017)
the Natural Science Foundation of Jiangsu of China (No. BK20180994)
the Fund for Postdoctoral Research in China (No. 2018M632382)
the Training Programs of Innovation and Entrepreneurship for College Students in Jiangsu Province (No. 201910313062Y)
Received: 26 April 2020
Accepted: 11 September 2020
First Online: 22 September 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee on Animal Research of Xuzhou Medical University (No. SCXK < SU > 2014–0003). The purpose of the study was explained to each participant. Written informed consent was provided by pregnant women.
: Not applicable.
: The authors declare that they have no competing interests.