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Article History

Received: 9 November 2020

Accepted: 30 April 2021

First Online: 13 May 2021

Declarations

:

: All study procedures were approved by the Ethics Committee of Shanghai First Maternity and Infant Hospital, affiliated with Tongji University (KS1512). This ethics was obtained by corresponding author, Xipeng Wang. We conducted research using identifiable electronic medical record data. The research project did not involve personal privacy and commercial interests and was no longer accessible to participants. Therefore, the ethics committee approved the waiver of signed written informed consent and approved the procedure for verbal consent. At the same time, after obtaining ethical approval, we tried to contact the participants before using the data and notified them by phone. A patient who couldn’t be reached by phone, whose data could be used directly. For participants with missing follow-up data, oral informed consent was obtained before the start of each telephone interview. All processes have been recorded and saved. Administrative permissions were required to access and use the medical records described in our study.

: Not applicable.

: The authors declare that they have no competing interests.