In 2017–2019, the March of Dimes convened a workgroup with biomedical, clinical, and epidemiologic expertise to review knowledge of the causes of the persistent Black-White disparity in preterm birth (PTB). 15University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.14March of Dimes, White Plains, NY, United States.13University of Georgia College of Public Health, Athens, GA, United States.12Brandeis University School for Social Policy and Management, Waltham, MA, United States.11School of Medicine, Oregon State University, Portland, OR, United States.10University of Colorado, Denver, CO, United States.9David Geffen School of Medicine at University of California, Los Angeles, CA, United States.8University of Pennsylvania School of Medicine, Philadelphia, PA, United States.7Northwestern University School of Medicine, Chicago, IL, United States.6Majaica LLC, Atlanta, GA, United States.5Stanford University School of Medicine, Stanford, CA, United States.4Albert Einstein College of Medicine, New York, NY, United States.3University of Washington School of Medicine, Seattle, WA, United States.2USC Suzanne Dworak-Peck School of Social Work, University of Southern California, Los Angeles, CA, United States.1School of Medicine, University of California, San Francisco, San Francisco, CA, United States.Wise 5, Gina Legaz 14, Kweli Rashied-Henry 14, Jordana Frost 14, Sarah Verbiest 15 and Lisa Waddell 14 † 10, Kent Thornburg 11, Dolores Acevedo-Garcia 12, José F. Driscoll 8, Terinney Haley 1, Julia Acker 1, Gary M. Stevenson 5, Fleda Mask Jackson 6, James W. Paula Braveman 1 *, Tyan Parker Dominguez 2, Wylie Burke 3, Siobhan M.