Shi, Tong
Lin, Yan-Kun
Bao, Qiao
Lao, Wei-Hua
Ouyang, Ke-Yu
Article History
Received: 2 April 2022
Accepted: 27 June 2022
First Online: 5 July 2022
Declarations
:
: The approval for the study was received by the ethics committee/Institutional Review Board of Guangdong Maternal and Child Health Hospital. The need for informed consent was waived by the ethics committee/Institutional Review Board of Guangdong Maternal and Child Health Hospital, because of the retrospective nature of the study. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013).
: Not applicable.
: The authors declare that they have no relevant financial interests.