Total leukocyte and neutrophil count changes associated with antenatal betamethasone administration in premature infants.

The white blood cell counts of 84 premature infants were included in a retrospective study of 45 infants treated antenatally with betamethasone and 39 non-treated infants. A significant increase in neutrophil and immature neutrophil forms was found in the treated group when the drug was administered to the mother close to delivery. This effect lasted for three days. Afterwards, although the counts were not significantly high compared to the control group, their physiological decrease was delayed. This study indicates that the known stimulating effect of steroids on total leukocyte and neutrophil counts in adult humans and fetal lambs, also occurs in premature infants. This fact supports recent reports which propose the antenatal maternal administration of betamethasone as a cause of leukemoid reaction or leukocytosis after birth.