Corticosteroid-induced leukocytosis in pregnancy: A prospective observational study.

Background: In the course of managing preterm labour, increasing trends of total white cell count raises concern for the obstetrician, suggesting a possible underlying infectious aetiology. Although mild leukocytosis is expected in pregnancy, the patterns of increment after corticosteroid administration are not well described beyond animal models and in a small number of human studies.
Methods: Seventy-three consecutive patients who required antenatal corticosteroids for either preterm labour or prelabour caesarean section were recruited and given a standard course of 12mg dexamethasone phosphate, twelve hours apart. Venous blood samples were taken before administration, at six hours and 36 hours after the first dose of dexamethasone.
Results: The total white count trend was 10.31±2.62 at baseline, 11.44±3.05 at six hours and 12.20±3.49 at 36 hours. Neutrophil-lymphocyte ratio was 3.60±1.31, 8.73±3.63 and 3.24±1.49 respectively, reflecting relative neutrophilia and lymphopenia which normalised by 36 hours.
Conclusion: In contrast to previous studies, we found only a slight increment in total white cell count of about 10%. The marginal changes described in our study would not normally raise any clinical concern, although vigilance should be exercised if higher levels were observed.