Received: 18 June 2020
Accepted: 24 August 2021
First Online: 12 September 2021
: This retrospective study was approved by the Institutional Ethical Review Board of Dalian Women and Children’s Medical Center (group), 154 Zhongshan Road, Dalian 116012, China (approval number 20003). Informed consent was waived due to the retrospective nature of this study. Written informed consent was obtained from all guardians for anonymized data analysis and publication.
: Not Applicable.
: The authors declare that they have no competing interests.