Funding for this research was provided by:
Eunice Kennedy Shriver National Institute of Child Health and Human Development (F32HD091945)
National Institute of Nursing Research (R01NR017020)
Maternal and Child Health Research Institute, Stanford University (N/A)
Received: 16 October 2018
Accepted: 28 December 2018
First Online: 9 January 2019
Ethics approval and consent to participate
: The State of California Committee for the Protection of Human Subjects and the Stanford University Research Compliance Office approved the study protocol. Informed consent was not obtained because the Institutional Review Boards deemed the research involved no more than minimal risk to the participants, the waiver would not adversely affect the rights and welfare of the participants, and the research could not practically be carried out without the waiver. Permission was obtained by the Institutional Review Boards to access the data used in the study.
: Not applicable.
: The authors declare that they have no competing interests.
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