Transfusion of Prematures Trial

Inclusion Criteria: * Birth weight less than or equal to 1000 grams. * Gestational age at least 22 weeks but less than 29 weeks * Admitted to the NICU within 48 hours of life Exclusion Criteria: * Considered nonviable by the attending neonatologist * Cyanotic congenital heart disease * Parents opposed to the transfusion of blood * Parents with hemoglobinopathy or congenital anemia * In-utero fetal transfusion * Twin-to-twin transfusion syndrome * Isoimmune hemolytic disease * Lack of parental consent * Severe acute hemorrhage, acute shock, sepsis with coagulopathy, or need for perioperative transfusion. * Prior blood transfusion on clinical grounds beyond the first 6 hours of life * Infant has received erythropoietin prior to randomization, or is intended to receive erythropoietin through the neonatal course * Congenital condition, other than premature birth, that adversely affects life expectancy or neurodevelopment. * High probability that the family is socially disorganized to the point of being unable to attend follow-up at 22-26 months.