[1] Oregon Health & Science University – Portland State University,School of Public Health
[2] University of California,Department of Obstetrics, Gynecology, and Reproductive Sciences
[3] San Francisco,California Preterm Birth Initiative
[4] University of California,Department of Epidemiology and Biostatistics
[5] San Francisco,Department of Pediatrics
[6] University of California,Department of Human Ecology
[7] San Francisco,Department of Public Health
[8] University of California,Sexual Health and Reproductive Equity Program, School of Social Welfare
[9] San Diego,Department of Psychiatry
[10] University of California,Department of Pediatrics
[11] Davis,Department of Family and Community Medicine
[12] Population Health Division,Department of Social and Behavioral Sciences
[13] University of California,undefined
[14] Berkeley,undefined
[15] University of California,undefined
[16] San Francisco,undefined
[17] University of California,undefined
[18] San Francisco,undefined
[19] Philip R. Lee Institute for Health Policy Studies,undefined
[20] University of California,undefined
[21] San Francisco,undefined
[22] Harvard School of Public Health,undefined
[23] Harvard University,undefined