Antenatal Steroids: Do They Affect Postnatal Blood Counts? † 1170

When given postnatally, corticosteroids are known to cause a leukocytosis. Corticosteroids are also used in the treatment of several immune mediated thrombocytopenias. However, little is known how prenatal steroids affect postnatal peripheral blood counts in preterm infants. Objective: to investigate the effect of prenatal steroids on postnatal blood counts. Methods: a retrospective analysis of very low birth weight infants(<1500 grams) born between 7/93 and 7/97 at a single level III NICU was performed. Peripheral blood counts of infants whose mothers received steroids(n= 147) were compared with a control group whose mothers did not receive steroids (n=127). Blood counts were compared on admission (within 1 hour of life) and on day of life 1-3. Statistical analysis was performed using repeated measures ANOVA with post hoc testing. Covariates used were gestational age, Apgar scores at 5 minutes, growth restriction and preeclampsia. Data are expressed as mean ± SD. Results: Platelet counts were higher on admission and on each day from day 1 through 3, in the steroid group as compared to the control group (admission: 228±67 mm³ vs 200±73 mm³, p <.001; day 1: 222±73 mm³ vs 195±73mm³, p <.001,day 2: 219±85 mm³ vs 195±93 mm³, p=.002, and day 3: 231±151 mm³ vs 192±88, mm³ p <.001). There were no statistical differences in total white blood cell counts or absolute neutrophil counts between the groups on admission or at any time from day 1-3. However, nucleated red blood cell counts (per 100 wbc) were found to be higher in the control group as compared to the steroid group on admission and on days 1-3 (admission: 78±129 vs 40±83, p<.001, day 1: 58±146 vs 36±129, p=.007, day 2: 58±167 vs 31±119, p=.002, day 3: 49±139 vs 18±53, p=.002). Conclusions: In our population, prenatal steroids are associated with an elevation in platelet counts and a decrease in nucleated red blood cell counts at birth and during the first 72 hours of life in very low birth weight infants. However, prenatal steroids have no effect on total white blood cell counts and absolute neutrophil counts during this time period. Further investigation is needed to determine the significance of this association.