Funding for this research was provided by:
National Natural Science Foundation of China (61603106)
Guangdong Science and Technology Department (2018B030335001)
Guangzhou Women and Children’s Medical Center (IP-2019-017)
Received: 15 November 2019
Accepted: 5 October 2020
First Online: 17 October 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee and Institutional Review Board of Guangzhou Women’s and Children’s Medical Center, Guangzhou, China, and conducted in accordance with the ethical guidelines of the Declaration of Helsinki of the World Medical Association (IRB No. 2019-06700). The requirement to obtain informed consent was waived because of the retrospective nature of the study. All data were deidentified before they were provided to the investigators.
: Not applicable.
: The authors declare that they have no competing interests.