1. Department of Gynecology and Obstetrics, Emory University School of Medicine , Atlanta, Georgia , USA
2. Center for Biostatistics in AIDS Research, Harvard T. H. Chan School of Public Health , Boston, Massachusetts , USA
3. Department of Pediatrics, Northwestern University Feinberg School of Medicine , Chicago, Illinois , USA
4. Department of Pediatrics, University of California, Los Angeles , Los Angeles, California , USA
5. Departments of Internal Medicine and Pediatrics, Massachusetts General Hospital , Boston, Massachusetts , USA
6. Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health , Boston, Massachusetts , USA
7. Department of Epidemiology, Harvard T. H. Chan School of Public Health , Boston, Massachusetts , USA
8. Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine , Chicago, Illinois , USA
9. Population Council, Center for Biomedical Research , New York, New York , USA