Venous and Arterial Hematologic Profiles of Very Low Birth Weight Infants

Abstract

Objective. In very low birth weight (VLBW) infants, diagnostic and therapeutic decisions depend on hematologic values. As few data are available, we studied the course during the first 6 weeks of life. Design. Four prospective longitudinal cohort studies were retrospectively combined assessing hematologic profiles of 562 VLBW infants. For characterization of red blood cells and iron, infants receiving erythropoietin were excluded. For characterization of white blood cells and platelets, infants receiving antibiotics were excluded. Results. The third (3rd)/median/97th percentiles on day 3 were as follows: hemoglobin: 11.0/15.6/19.8 g/dL; hematocrit: 35/47/60%; red blood cells: 3.2/4.2/5.3 × 1012/L; reticulocytes: .6/7.1/27.8%; platelets: 58/203/430 × 109/L; white blood cells: 3.6/9.5/38.3 × 109/L; neutrophils: .7/4.7/25.3 × 109/L; ferritin: 27/140/504 ng/mL; iron: .8/7.5/26.7 μmol/L; transferrin saturation: 2.6/22.7/79.8%. Transferrin saturation was <24% in 51%, ferritin concentration <100 ng/mL in 32%, and platelets <150 × 109/L in 29% of this population. The steady decrease of red cell parameters was mitigated by transfusions. Neutrophils decreased steadily, and were <1.75 × 109/L in 35% at 6 weeks. Conclusions. Iron indices and platelet counts on day 3 and neutrophil counts at 2 to 6 weeks of age are lower than previously assumed in VLBW infants and lower than in larger prematures.