Preterm infants regularly need Packed red blood cell transfusions. This life-saving therapy can help prevent anaemia of prematurity and in turn, safeguard normal organ function. However, there is a risk that donor blood contains the heavy metals mercury (Hg), lead (Pb) and Cadmium (Cd) which are known developmental neurotoxicants and may be present in neurotoxic doses. In this episode we meet Alison Falck, Assistant Professor of Pediatrics at the University of Maryland School of Medicine who has studied the relationship between the donor concentration, number of transfusions and exposure in preterm infants. Her results may have implications for prescreening of donor blood.