Platelet aggregation in neonates with hyperbilirubinaemia.

In 19 jaundiced newborns who had no evidence of kernicterus the effect of bilirubin on adenosine-5'-diphosphate (ADP), epinephrine and collagen-induced platelet aggregation was studied. Compared to 20 normal adult controls, no significant difference was found for ADP and collagen-induced platelet aggregation in jaundiced infants. However, with epinephrine, significantly decreased aggregation was observed, but this was also the case for non-jaundiced infants. This suggests that the reduced response to epinephrine in hyperbilirubinaemic infants is related to age rather than to bilirubin. Increased bilirubin is therefore not responsible for any increased bleeding tendency due to impaired platelet function.