title: Thrombocytopenia in neonates with polycythemia: incidence, risk factors and clinical outcome.
abstract: BACKGROUND
  Polycythemia occurs in 1 to 5% of neonates and is associated with complications, including an increased risk of thrombocytopenia.
  
  
  OBJECTIVE
  To evaluate incidence, risk factors, management and outcome of thrombocytopenia in neonates with polycythemia.
  
  
  METHODS
  All neonates with polycythemia admitted to our neonatal intensive care unit between 2006 and 2013 were included in this retrospective study. We evaluated the incidence of thrombocytopenia (platelet count <150 × 10(9)/l) and severe thrombocytopenia (platelet count <50 × 10(9)/l) and the correlation between platelet counts and hematocrit values.
  
  
  RESULTS
  The incidence of thrombocytopenia and severe thrombocytopenia was 51 (71/140) and 9% (13/140), respectively. Platelet count was negatively correlated with hematocrit (spearman correlation coefficient -0.233, p = 0.007). After multiple regression analysis, we found an independent association between thrombocytopenia and being small for gestational age (OR: 10.0; 95%; CI: 1.2-81.7; p = 0.031).
  
  
  CONCLUSIONS
  Thrombocytopenia occurs in 51% of neonates with polycythemia and is independently associated with growth restriction. Increased hematocrit is associated with decreased platelet count.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Roos D
authors.initials: RD
authors.lastname: Vlug
authors.forename: Enrico
authors.initials: E
authors.lastname: Lopriore
authors.forename: Marleen
authors.initials: M
authors.lastname: Janssen
authors.forename: Johanna M
authors.initials: JM
authors.lastname: Middeldorp
authors.forename: Mirjam E A
authors.initials: ME
authors.lastname: Rath
authors.forename: Vivianne E H J
authors.initials: VE
authors.lastname: Smits-Wintjens
mesh_terms: D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D011086:Polycythemia / Q000097:blood / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013921:Thrombocytopenia / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology*; D016896:Treatment Outcome
keywords: Polycythemia; growth restriction; hyperviscosity; neonates; thrombocytopenia