1. Department of Biology and Public Health ProgramSanta Clara University Santa Clara California
2. Department of Family, Population and Preventive MedicineStony Brook University Stony Brook New York
3. Division of Environmental Health Sciences, School of Public HealthUniversity of California, Berkeley Berkeley California
4. Division of Epidemiology, School of Public HealthUniversity of California, Berkeley Berkeley California
5. Preterm Birth InitiativeUniversity of California, San Francisco San Francisco California
6. School of Public HealthUniversity of California, Berkeley Berkeley California