Leukocytosis as a prognostic marker in the development of fetal inflammatory response syndrome

OBJECTIVE: To identify and evaluate the correlation between leukocyte count in maternal blood and the risk of developing fetal inflammatory response syndrome (FIRS). PATIENTS AND METHODS: The study involved 158 infants born at 22−34 weeks of gestation and their mothers. Umbilical cord blood cytokines were evaluated in immunoassay tests and maternal blood was tested for the leukocyte formula. RESULTS: The period of gestation was significantly shorter in the FIRS group compared to the control group (29.5±3.1 vs. 32.2±2.4 weeks, p<0.001). Gestational age was ≤30 weeks for 53.8% of the newborns in the FIRS group and 15.8% of the newborns in the control group (p<0.001). The number of leukocytes in maternal blood before and during labor was significantly higher in the FIRS group than in the control group (p=0.034 and 0.004, respectively). The study determined the correlation between the total leukocyte count in maternal blood and IL-6 concentration during labor (p=0.05) and tumor necrosis factor (TNF-α) concentration in umbilical cord blood before and during labor (p=0.02 and 0.007, respectively). CONCLUSION: Leukocytosis in the FIRS group was significantly higher than in the control group before and during labor. According to our data, one of the possible indicators of intrauterine infection could be the number of leukocytes in maternal blood.