Abstract

Serial blood leucocyte counts were made on 35 ill preterm and term babies during the first 28 days of life.

Ill babies with no clinical or bacteriological evidence of infection showed no changes in the blood leucocytes during the neonatal period when compared with normal babies.

The changes in the blood leucocytes in babies with proven or suspected bacterial infection were an increase in the absolute values of polymorphonuclear neutrophils, an increase in the absolute values of immature neutrophils, a significant fall in polymorphonuclear neutrophils (below 1000/mm³) and in eosinophils (down to 0) in very ill babies, and toxic granulation of neutrophils.