[1] University of California,Department of Obstetrics, Gynecology and Reproductive Sciences
[2] San Francisco,Department of Pediatrics
[3] University of California,Department of Family Health Care Nursing
[4] San Diego,California Preterm Birth Initiative
[5] University of California,Division of Neonatal & Developmental Medicine, Department of Pediatrics
[6] San Francisco,Department of Obstetrics and Gynecology
[7] University of California,Department of Epidemiology and Biostatistics
[8] San Francisco,Rory Meyers College of Nursing
[9] Stanford University,undefined
[10] California Perinatal Quality Care Collaborative,undefined
[11] Stanford University,undefined
[12] University of California,undefined
[13] San Francisco,undefined
[14] New York University,undefined