Red cell distribution width (RDW) in the newborn: normative data

To evaluate the normal range of red blood cell distribution width (RDW) in term and preterm newborns dependent on gestational age.

A total of 1,594 preterm and term neonates were admitted to our neonatology department. Infants were divided into two groups according to their gestational age. Group 1 consisted of infants with ≤34 weeks of gestation; group 2 consisted of infants with ≥35 weeks of gestation. Infants in Groups I and II were subdivided according to their gestational age. Gestational age, birth weight, sex, hemoglobin and hematocrit, MCV levels of all newborns were recorded, and RDW was compared between the groups.

A total of 1,594 newbornswere enrolled in the study. Group 1 (≤34 weeks) consisted of 725 newborns and Group 2 (≥35 weeks) consisted of 869 newborns. The mean normal range of RDW in Group 1 was 17.8 ± 2.1 and of group II was 16.7 ± 1.6 (P<0.05). The normal range for RDW values at 32-34 weeks was higher than at 35-36 gestational weeks, and at 37-42 weeks (P = 0.002 and 0.003).

RDW values at ≤34 weeks in newborns are higher than at ≥35 weeks. This may be useful in the differential diagnosis of neonatal hematologic diseases together with other red cell parameters.