Text and Data Mining valid from 2019-02-15
Received: 10 August 2018
Accepted: 24 January 2019
First Online: 15 February 2019
Ethics approval and consent to participate
: All patients provided their informed written consent. The study was approved by the Ethics Committee of Shenyang Women’s and Children’s Hospital and was conducted in accordance with the principles of the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.
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