Letter to the Editor in response to: Fetal haemoglobin levels in premature newborns

Gavulic et al. recently reported that fetal hemoglobin (HbF) concentrations in preterm neonates rapidly decrease after red blood cell (RBC) transfusions, significantly diverging from expected HbF values.1 The authors indicated that this was the first demonstration of a change in physiologic HbF levels after transfusion in these patients. In reality, De Halleux et al.2 in 2002 addressed the same issue in a series of 11 preterm neonates with gestational age (GA) at birth ranging from 23 to 27 weeks.