1. From the Joint Program in Neonatology (Brigham and Women's Hospital, Children's Hospital, Beth Israel Deaconess Medical Center, and Harvard Medical School) Boston, Massachusetts;
2. Department of Maternal and Child Health, Harvard School of Public Health; Boston, Massachusetts;
3. Division of Hematology, Department of Medicine and Division of Transfusion Medicine, Department of Laboratory Medicine and
4. Division of Neonatology, Georgetown University Hospital, Washington, DC; and the
5. Division of Hematology, Department of Medicine, Harvard Medical School, and Director of the Blood Bank, Brigham and Women's Hospital, Boston, Massachusetts.