Funding for this research was provided by:
Health Commission of Zhejiang Province (NO.2014KYA273, NO.2014KYB356)
Ningbo Municipal Bureau of Science and Technology (NO.2014B82003)
Air pollution and Health Research Center, Zhejiang University (NO.519600-I21502)
Ningbo Women and Children's Hospital (NO.2010A22011)
Text and Data Mining valid from 2018-09-20
Received: 14 November 2017
Accepted: 12 September 2018
First Online: 20 September 2018
Ethical approval and consent to participate
: This study did not contain confidential patient data. Committee of ethics, Ningbo Women and Children’s Hospital approved this study. The patient’s consent to participate is not applicable in this study.
: Not applicable.
: The authors declare that they have no competing interests.
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