Text and Data Mining valid from 2019-06-07
Received: 5 April 2019
Accepted: 29 May 2019
First Online: 7 June 2019
Ethics approval and consent to participate
: All human subjects provided written, informed consent to participate in accordance with the Declaration of Helsinki before sample collection. The protocols and informed consent forms used in this study were reviewed and approved by the Scientific and Ethical Committee of Guangzhou Women and Children’s Medical Center.
: Not applicable.
: The authors declare that they have no competing interests.