Platelet ultrastructure of high-risk premature infants.

Hemorrhagic and thrombotic complications are common in the term and preterm infant. Limited information is currently available about neonatal platelet structure and function, and how these may predispose infants to bleeding problems. This study comparing platelet ultrastructure of 71 different term and preterm infants with that of 15 adult control subjects revealed certain platelet morphological differences. Specifically, the adult platelets had more pseudopods, larger glycogen deposits, more visible microtubular structure, markedly fewer alpha granules, and smaller areas/perimeters than the infant platelets. Also, in infants greater than 31 weeks gestation, the platelets of vaginally-delivered infants were larger than those of both infants delivered by C-section and normal adults. These differences in platelet size and morphology may be related to developmental differences and/or the stress of delivery. These findings provide a framework for further exploration of neonatal platelet structure and function.