Objective. In very low birth weight (VLBW) infants, diagnostic and therapeu
tic decisions depend on hematologic values. As few data are available, we s
tudied the course during the first 6 weeks of life.
Design. Four prospective longitudinal cohort studies were retrospectively c
ombined assessing hematologic profiles of 562 VLBW infants. For characteriz
ation of red blood cells and iron, infants receiving erythropoietin were ex
cluded. For characterization of white blood cells and platelets, infants re
ceiving 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 X 10(12)/L; reticulocytes: .6/7.1/27.8%; platelets: 58/203/430 X
10(9)/L; white blood cells: 3.6/9.5/38.3 X 10(9)/L; neutrophils: .7/4.7/25.
3 X 10(9)/L; ferritin: 27/140/504 ng/mL; iron: .8/7.5/26.7 mu mol/L; transf
errin saturation: 2.6/22.7/79.8%. Transferrin saturation was <24% in 51%, f
erritin concentration <100 ng/mL in 32%, and platelets <150 X 10(9)/L in 29
% of this population. The steady decrease of red cell parameters was mitiga
ted by transfusions. Neutrophils decreased steadily, and were <1.75 X 10(9)
/L in 35% at 6 weeks.
Conclusions. Iron indices and platelet counts on day 3 and neutrophil count
s at 2 to 6 weeks of age are lower than previously assumed in VLBW infants
and lower than in larger prematures.