Funding for this research was provided by:
Beijing Municipal Science and Technology Commission (Z181100001718108)
The National Key Research and Development Program of Chin (2016YFC1000101)
Beijing Municipal Administration of Hospitals’ Ascent Pla (DFL2015130)
Text and Data Mining valid from 2020-03-12
Received: 13 November 2019
Accepted: 2 March 2020
First Online: 12 March 2020
Ethics approval and consent to participate
: Ethical approval was provided by the Human Research Ethics Committee, Beijing Obstetrics and Gynecology Hospital, Capital Medical University (No.2019-KY-046-01).All subjects authorized the using of the data for reference by signing the consent form. (No. BJOGH201711PDC2, available since 12/20/2017; No. BJOGH201810PDC3, available since 12/06/2018).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.
: All patients in this report provided their consent for publication.
: The authors declare that they have no competing interests.