Diagnostische und therapeutische Entscheidungen hängen bei der Behandlung von VLBW Frühgeborenen ( / 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. Four prospective longitudinal cohort studies were retrospectively combined assessing hematologic profiles of 562 VLBW infants. We showed by metaanalysis that the values between the different four studies are not significantly different. For characterization of red blood cells and ferritin, infants receiving erythropoietin were excluded. For characterization of white blood cells and platelets, infants receiving antibiotics were excluded. Red cell parameters of VLBW infants were significantly lower than those of mature newborns. 29% of VLBW infants have thromboctopenia at the age of 3 days. Neutrophils decreased steadily, and were