Thrombocytopenia in Small-for-Gestational-Age Infants

Abstract

BACKGROUND Thrombocytopenia is common among small for gestational age neonates (SGA; birth weight <10th % 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 nine 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 vs. 10% of non-SGA matched-controls (p<0.0001). One hundred-two of the 905 had a recognized cause of thrombocytopenia (DIC, early-onset sepsis, ECMO). This group had a 65% mortality rate. The remaining 803 did not have an obvious cause for their thrombocytopenia. We termed these the “thrombocytopenia of SGA”. They had a mortality rate of 2% (p<0.0001) and a mean nadir count on day 4 of 93,000/μL (standard deviation, 51,580/μL, 10th % 50,000/μL, 90th % 175,000/μL). By day 14, platelet counts were ≥150,000/μL in >half of the patients. Severely SGA neonates (<1st %) had lower counts and longer thrombocytopenia duration (p<0.001). High nucleated red cell counts at birth correlated with low platelets (p<0.0001). Platelet transfusions were given to 23% and counts typically >tripled. Thrombocytopenia was associated with SGA status more so than with the diagnosis of maternal preeclampsia. CONCLUSIONS SGA neonates with clearly recognized varieties of thrombocytopenia have a high mortality rate. In contrast the “thrombocytopenia of SGA” is a hyporegenerative condition of moderate severity and two weeks duration, associated with evidence of intrauterine hypoxia, and associated with a low mortality rate.

Neonatal thrombocytopenia—causes and outcomes following platelet transfusions

“…The risk of hemorrhage was found to be associated with lower gestational age, definite causes of thrombocytopenia, and the severity of concomitant morbidities [11, 17, 25]. …”

The immature platelet fraction: creating neonatal reference intervals and using these to categorize neonatal thrombocytopenias

“…Neonates with thrombocytopenia were categorized into the following three groups, based on the presumed mechanism of the thrombocytopenia: (1) hyporegenerative, (2) consumptive or (3) indeterminate. Hyporegenerative thrombocytopenias were either congenital genetically based syndromes known to have hyporegenerative thrombocytopenia, 11 Trisomy 21, 18 and 13, 12 the hyporegenerative thrombocytopenia of small for gestational age (SGA) 13 or the hyporegenerative thrombocytopenia of birth asphyxia 14 . Consumptive thrombocytopenias were either immune-mediated (allo-immune or maternal autoimmune), or accompanying infection, necrotizing enterocolitis (NEC) or disseminated intravascular coagulation (DIC) 15 – 18 .…”

Early-Onset Neutropenia in Small-for-Gestational-Age Infants

“…The weak to moderate association between fetal hypoxia and neonatal neutropenia is similar to the relationship we reported between NRBC and platelet counts in the first week, which we speculated was an effect of intrauterine hypoxia on increased red blood cell production with a subsequent reduction in platelet and neutrophil production. 15,20 The 201 neonates with neutropenia of SGA had I/T ratios, as a measure of the leukocyte "left shift," within the normal reference range of 0.00 to 0.25. Moreover, the I/T ratios of these 201 were not different from those of the group of 3443 SGA neonates who did not have neutropenia.…”

“…Neonates were classified as SGA if their weight at birth was ,10th percentile for gestational age, using normative values from our Intermountain Healthcare population. 15 Severity of SGA was classified according to 3 categories: severe, less than first percentile; moderate, first to fifth percentile; and mild, sixth to 10th percentile. Cases of maternal hypertension were identified from case-mix records using International Classification of Diseases, Revision 9 definitions 6425 (severe preeclampsia), 6426 (eclampsia), or 6427 (preeclampsia or eclampsia superimposed on existing hypertension).…”