title: Thrombocytopenia in Small-for-Gestational-Age Infants.
abstract: BACKGROUND
  Thrombocytopenia is common among small-for-gestational-age (SGA) neonates (birth weight <10th percentile reference range), but several aspects of this thrombocytopenia are unclear, including the incidence, typical nadir, duration, association with preeclampsia, mechanism, and risk of death.
  
  
  METHODS
  Using 9 years of multihospital records, we studied SGA neonates with ≥2 platelet counts <150,000/μL in their first week.
  
  
  RESULTS
  We found first-week thrombocytopenia in 31% (905 of 2891) of SGA neonates versus 10% of non-SGA matched controls (P < .0001). Of the 905, 102 had a recognized cause of thrombocytopenia (disseminated intravascular coagulation, early-onset sepsis, or extracorporeal membrane oxygenation). This group had a 65% mortality rate. The remaining 803 did not have an obvious cause for their thrombocytopenia, and we called this "thrombocytopenia of SGA." They had a mortality rate of 2% (P < .0001) and a mean nadir count on day 4 of 93,000/μL (SD 51,580/μL, 10th percentile 50,000/μL, 90th percentile 175,000/μL). By day 14, platelet counts were ≥150,000/μL in more than half of the patients. Severely SGA neonates (<1st percentile) had lower counts and longer thrombocytopenia duration (P < .001). High nucleated red cell counts at birth correlated with low platelets (P < .0001). Platelet transfusions were given to 23%, and counts typically more than tripled. Thrombocytopenia was more associated with SGA status than with the diagnosis of maternal preeclampsia.
  
  
  CONCLUSIONS
  SGA neonates with clearly recognized varieties of thrombocytopenia have a high mortality rate. In contrast, thrombocytopenia of SGA is a hyporegenerative condition of moderate severity and 2 weeks' duration and is associated with evidence of intrauterine hypoxia and a low mortality rate.
authors.affiliation: Divisions of Hematology/Oncology, and Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah; Primary Children's Hospital, Salt Lake City, Utah; robert.christensen@hsc.utah.edu.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Christensen
authors.affiliation: Women and Newborn's Clinical Program, Intermountain Healthcare, Salt Lake City, Utah;
authors.forename: Vickie L
authors.initials: VL
authors.lastname: Baer
authors.affiliation: Primary Children's Hospital, Salt Lake City, Utah;
authors.forename: Erick
authors.initials: E
authors.lastname: Henry
authors.affiliation: Statistical Data Center, LDS Hospital, Salt Lake City, Utah; and.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Snow
authors.affiliation: Statistical Data Center, LDS Hospital, Salt Lake City, Utah; and.
authors.forename: Allison
authors.initials: A
authors.lastname: Butler
authors.affiliation: Division of Neonatal Medicine, Children's Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Martha C
authors.initials: MC
authors.lastname: Sola-Visner
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D012189:Retrospective Studies; D013921:Thrombocytopenia / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology