Funding for this research was provided by:
institutional funding of Youth medicine research and development program for Reproductive Medicine from Chinese Medical Association (17020150684)
Guangzhou Women and Children’s Medical Center (Pre-NSFC-2016-006)
Text and Data Mining valid from 2020-01-13
Received: 20 August 2019
Accepted: 9 December 2019
First Online: 13 January 2020
Ethics approval and consent to participate
: This study was approved by the Reproductive Medical Ethics Committee of Guangzhou Women and Children’s Hospital. Written informed consent was obtained from each couple.
: The patients in this study provided their consent for its publication.
: The authors declare that they have no competing interests.