Funding for this research was provided by:
Science and Technology Planning Project of Guangzhou (201902010005)
Received: 10 January 2020
Accepted: 12 August 2020
First Online: 20 August 2020
Ethics approval and consent to participate
: This study was approved by the Reproductive Medicine Ethics Committee of the Third Affiliated Hospital of Guangzhou Medical College. The written informed consent was obtained from all of the participants.
: We obtained written informed consent for publication of identifying images or other personal or clinical details of the participants.
: The authors declare that they have no competing interests.