Changes in leukocyte, granulocyte and lymphocyte counts following antenatal betamethasone administration to pregnant women.

OBJECTIVE: Preterm labor and premature rupture of membranes are associated with a mild leukocytosis. However, we have observed a higher maternal leukocyte count after antenatal betamethasone therapy. We planned this study to evaluate the effects of antenatal betamethasone treatment on maternal leukocyte, granulocyte and lymphocyte count.
METHODS: Forty-six pregnant women with the diagnosis of preterm labor between 28 and 33 weeks of gestation age received 12 mg betamethasone at a 12-h interval. The control group consisted of 50 pregnant women between 28 and 33 weeks of gestational age with no medical or obstetrics problems. After a baseline venous sampling, serial leukocyte, granulocyte and lymphocyte counts were obtained every 6 h until it returned to baseline value.
RESULTS: There were no statistically significant differences in the control group with respect to the total leukocyte, lymphocyte, and neutrophil count. Total leukocyte and granulocyte counts were increased by 29.8% and 17.8% within 24 and 12 h after betamethasone injection, respectively (P < 0.01). A significant reduction in lymphocyte count was observed within 12 h (45.4%) after betamethasone injection (P < 0.01). All changes in leukocyte, granulocyte and lymphocyte counts returned to baseline values within 3 days.
CONCLUSION: Antenatal betamethasone therapy leads to an increase in maternal leukocyte count and a decrease in lymphocyte count. This effect is transient and any leukocytosis persisting for more than 3 days is not due to betamethasone administration.