Thrombocytopenia in the newborn

© 2019 Elsevier Inc. All rights reserved. Neonatal thrombocytopenia remains a common clinical problem although most episodes are mild and resolve spontaneously. Most early-onset thrombocytopenias are due to impaired fetal megakaryocytopoiesis associated with placental insufficiency/fetal hypoxia. Severe early-onset thrombocytopenia (presenting < 72 hours of life) is usually due to congenital or perinatal infections, asphyxia or fetal/neonatal alloimmune thrombocytopenia (FNAIT) while late-onset thrombocytopenia (presenting after 72 hours) is usually due to sepsis and/or necrotizing enterocolitis (NEC). Major hemorrhage is uncommon in stable neonates with severe thrombocytopenia while clinically unstable neonates often have a poor outcome. Currently, the only therapy is platelet transfusion. However, there is wide variation in platelet transfusion thresholds worldwide and frequent deviation from transfusion guidelines. Controlled trials of platelet transfusion for severe neonatal thrombocytopenia, now underway, aim to identify the best regimens to treat and prevent hemorrhage and target therapy to neonates at highest risk. In future, improved understanding of fetal/neonatal megakaryocytopoiesis and TPO mimetics may benefit neonates with prolonged thrombocytopenia.