From the Department of Neonatology, National Maternity Hospital, Dublin (A.C.), and University Maternity Hospital Limerick, Limerick (R.K.) - both in Ireland; Department of Transfusion Medicine, National Health Service (NHS) Blood and Transplant, the Department of Haematology, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, the Radcliffe Department of Medicine, University of Oxford, and Oxford Biomedical Research Centre Haematology Theme, Oxford (S.J.S.), the Department of Obstetrics and Gynaecology, University of Cambridge (K.W.), NHS Blood and Transplant, Clinical Trials Unit (K.W., C.H., A. Deary, R.H., V.H., A.M., C.L.), and the Neonatal Intensive Care Unit, Cambridge University Hospitals NHS Trust (A. D'Amore), Cambridge, the Neonatal Intensive Care Unit, Evelina London Children's Hospital, Guy's and St. Thomas' NHS Foundation Trust (B.L.S., T.W.), NHS Blood and Transplant (H.N.), and the Department of Hematology, Imperial College London (H.N.), London, and the Neonatal Intensive Care Unit, Norfolk and Norwich University Hospitals NHS Foundation Trust, and Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich (P.C.) - all in the United Kingdom; the Center for Clinical Transfusion Research, Sanquin Blood Supply (S.F.F.-G., K.F.), and the Departments of Epidemiology (S.F.F.-G.) and Neonatology (E.L.), Leiden University Medical Center, Leiden, and the Departments of Pediatric Hematology (S.F.F.-G., K.F.) and Neonatology (W.O.), Emma Children's Hospital, Academic Medical Center, Amsterdam - both in the Netherlands; and the Neonatal Intensive Care Unit, Cloudnine Hospital, Bangalore, India (V.V.).