Funding for this research was provided by:
the National Key Research and Development Program (2016YFC1000505, 2018YFC1002801)
the Innovation-oriented Science and Technology Grant from NPFPC Key Laboratory of Reproduction Regulation (CX2017-06)
Received: 13 September 2018
Accepted: 3 January 2019
First Online: 11 January 2019
Ethics approval and consent to participate
: The study was approved by the ethical review committee of Shanghai Institute of Planned Parenthood Research (SIPPR). The study was conducted according to the Declaration of Helsinki. The women participating in the study provided their written informed consent before the study was carried out.
: Not applicable.
: The authors declare that they have no competing interests.
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