Funding for this research was provided by:
National Natural Science Foundation of China (81703233, 81673179, 81602860)
Shanghai Municipal Population and Family Planning Commission (20184Y0078, 20174Y0100)
Shanghai Sailing Program (18YF1419600)
Fundamental Research Funds for Central Universities (22120180038)
Received: 20 December 2018
Accepted: 23 April 2019
First Online: 16 May 2019
Ethics approval and consent to participate
: The Human Ethics Committee of Shanghai First Maternity and Infant Hospital approved the study, and all participating mothers provided written informed consent prior to participation.
: Not applicable
: The authors declare that they have no competing interests.
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