Affiliation: | 1. Department of Paediatrics, University of California San Francisco, San Francisco, California;2. Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California California Preterm Birth Initiative, University of California San Francisco, San Francisco, California;3. California Preterm Birth Initiative, University of California San Francisco, San Francisco, California;4. California State University, Fresno, California;5. Department of Paediatrics, University of California San Francisco, San Francisco, California California Preterm Birth Initiative, University of California San Francisco, San Francisco, California;6. Calit2/Qualcomm Institute, University of California San Diego, La Jolla, California;7. Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa |