University of California, San Francisco (UCSF) - Department of Obstetrics and Gynecology, University of California, San Diego (UCSD) - Department of Pediatrics, University of California, San Francisco (UCSF), University of California, San Francisco (UCSF) - Department of Obstetrics and Gynecology, University of California, San Francisco (UCSF) - Department of Obstetrics and Gynecology, Columbia University - Department of Environmental Health Sciences, University of California, San Francisco (UCSF) - Department of Obstetrics and Gynecology, University of California, San Francisco (UCSF) - Department of Biological and Medical Informatics, University of California, San Francisco (UCSF) - Department of Psychiatry and Behavioral Sciences, University of California, San Francisco (UCSF) - School of Nursing, University of California, San Francisco (UCSF) - California Preterm Birth Initiative, University of California, Berkeley - School of Social Welfare, University of California, San Francisco (UCSF) - Department of Pediatrics, University of California, San Francisco (UCSF) - Department of Obstetrics, Gynecology and Reproductive Sciences, Stanford University - Department of Genetics, University of California, San Francisco (UCSF) - Department of Epidemiology and Biostatistics, University of California, San Francisco (UCSF), University of California, San Francisco (UCSF) - Department of Epidemiology and Biostatistics, University of California, San Francisco (UCSF) - Division of Pediatric Hospital Medicine, University of California, San Francisco (UCSF) - Newborn Brain Research Institute, University of California, San Francisco (UCSF) - Aging, Metabolism and Emotions Center, University of California, Davis - Department of Public Health Sciences, University of California, San Francisco (UCSF) - Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco (UCSF) - Department of Obstetrics, Gynecology and Reproductive Sciences, San Francisco Department of Public Health, University of California, San Francisco (UCSF) - Department of Obstetrics and Gynecology, University of California, San Francisco (UCSF) - Department of Obstetrics, Gynecology and Reproductive Sciences and University of California, San Francisco (UCSF) - Department of Epidemiology and Biostatistics

University of North Carolina (UNC) at Chapel Hill, University of Washington, University of Minnesota, Cornell University - Weill Cornell Medicine, affiliation not provided to SSRN, University of California, Berkeley - School of Social Welfare and The Alan Guttmacher Institute