Funding for this research was provided by:
National Natural Science Foundation of China (81741013)
Text and Data Mining valid from 2019-02-07
Received: 14 November 2018
Accepted: 30 January 2019
First Online: 7 February 2019
Ethics approval and consent to participate
: The study was approved by the Ethics Committees of the International Peace Maternity and Child Health Hospital, and the patient provided written informed consent.
: Written informed consent was obtained from this patient.
: The authors declare that they have no competing interests.
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