Funding for this research was provided by:
the 2016 Applied Medicine Research Project of Health and Family Planning Commission of Hefei (hwk2016yb011)
Received: 24 November 2018
Accepted: 26 July 2020
First Online: 5 August 2020
Ethics approval and consent to participate
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards and were approved by the Institutional Ethics Committee of Anhui Women and Child Health Care Hospital. Written informed consent was obtained from each parturient before enrollment in the study according to the process of informed consent by the Institutional Ethics Committee of Anhui Women and Child Health Care Hospital.
: The manuscript does not contain any individual person’s data; hence, consent for publication is not applicable.
: The authors declare that they have no competing interests.