The Role of Platelets in Premature Neonates with Intraventricular Hemorrhage: A Systematic Review and Meta-Analysis.

Intraventricular hemorrhage (IVH) affects up to 22% of extremely low birth weight neonates. Impaired coagulation might contribute to the pathogenesis of IVH. The aims of this study were to summarize the current knowledge on the role of platelet indices in premature neonates with IVH and to provide an overview of secondary hemostasis parameters as well as fibrinolysis in premature neonates with IVH. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases PubMed, Embase, Scopus, and Web of Science were searched on March 7, 2019, without time restrictions. In total, 30 studies were included. Most studies investigated the significance of platelet counts and/or mean platelet volume (MPV). The meta-analysis showed that at day 1 of life, neither platelet count nor MPV differed significantly between neonates with or without IVH (standardized mean difference [SMD]: -0.15 × 109 /L, 95% confidence interval [CI]: -0.37 to 0.07 and SMD: 0.22 fl, 95% CI: -0.07 to 0.51, respectively). However, platelet counts < 100 × 109 /L were associated with an increased risk of IVH. Secondary hemostasis parameters did not differ between neonates with and without IVH. Fibrinolysis was only sparsely investigated. In conclusion, platelet counts < 100 × 109 /L were associated with an increased risk of IVH in premature neonates. The impact of secondary hemostasis was only sparsely investigated but seemed to be minor, and the role of fibrinolysis in IVH in premature neonates needs further research. Whether reduced platelet function is associated with an increased risk of IVH in premature neonates remains to be investigated.