Funding for this research was provided by:
National Natural Science Foundation of China (81800448)
Guangzhou Science, Technology and Innovation Commission (201707010369)
Guangdong Medical Research Foundation (2017409)
Guangzhou Municipal Health and Family Planning Commission (20171A011258)
Received: 14 April 2019
Accepted: 6 August 2019
First Online: 13 August 2019
Ethics approval and consent to participate
: This project was reviewed and approved by the institutional review board of Guangzhou Women and Children’s Medical Center. Informed consent was obtained from all individual participants or their caregivers.
: Not applicable.
: The authors declare that they have no competing interests.