*Philip R. Lee Institute for Health Policy Studies

†School of Medicine

‡University of California San Francisco Library

§California Preterm Birth Initiative, University of California, San Francisco, California

∥Department of Human Ecology, University of California, Davis

¶Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, Illinois

This work was supported by the Agency for Healthcare Research and Quality (S.B.G.: AHRQ T32HS022241); the California Preterm Birth Initiative (S.B.G., B.C., and F.M.); and National Institutes of Health (B.C.: NIMHD K01MD015785; M.A.S.: NIMHD R01MD014068, NIMHD R01MD016280; and S.B.G.: National Center for Advancing Translational Sciences through UCSF-CTSI KL2 KL2 TR001870). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or AHRQ. Funding sources had no involvement in the study design; collection, analysis, or interpretation of data; writing of the report; or decision to submit the article for publication.

Interested parties may contact the first author to inquire about accessing the data spreadsheet.

B.C. and M.A.S. equally contributed to the work.

S.B.G. had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

The authors declare that they have nothing to disclose. In the spirit of full transparency, we report that two of the coauthors (B.C. and M.A.S.) are principal investigators of projects that appear in the scoping review. We have taken multiple steps to minimize bias in our review and to ensure the description of their studies are similar in length and tone to the other described studies.

Correspondence: Sarah B. Garrett, PhD, Philip R. Lee Institute for Health Policy Studies, San Francisco, CA. E-mail: [email protected]