1. Department of OBGYN, Maternal Fetal Medicine; Oregon Health & Science University; Portland Oregon
2. Slone Epidemiology Center; Boston University; Boston Massachusetts
3. Department of Biostatistics; Boston University School of Public Health; Boston Massachusetts
4. Harvard T.H. Chan School of Public Health, Kresge Building, Room 816B; Boston Massachusetts
5. Department of Epidemiology; Boston University School of Public Health; Boston Massachusetts
6. Massachusetts Department of Public Health; Massachusetts Center for Birth Defects Research and Prevention; Boston Massachusetts