Funding for this research was provided by:
Society of Family Planning (SFPRF10-2)
Received: 1 February 2018
Accepted: 10 May 2018
First Online: 14 June 2018
Ethics approval and consent to participate
: This study was approved by the institutional review board of the University of California, San Francisco (16-20371).
: No consent for publication was required.
: The authors declare that they have no competing interests.
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