The Comparison of Second Trimester Screening Tests With the White Blood Cell Counts

Objective: Our aim was to determine the possible differences in the maternal immune system by comparing white blood cells (WBCs) count with the sub-parameters in pregnant women with high-risk and no-risk for seconder trimester screening. Materials and Methods: The results of complete blood count (CBC) and second trimester screening (STS) tests made between January 2011 and September 2015 of women meeting the inclusion criteria were analyzed retrospectively. All test results of pregnant women with high-risk for trisomy 21 (n = 55), neural tube defect (NTD) (n = 45) and with no-risk (n = 55) were compared. Trisomy 18 could not be evaluated due to limited number of cases. Results: The monocyte count (P < 0.001) of T21 group were significantly increased compared to control group, but neutrophil to lymphocyte ratio (N/L) (P = 0.027), lymphocyte to monocyte ratio (L/M) (P < 0.001) and neutrophil to monocyte ratio (N/M) (P < 0.001) were significantly decreased. The WBC (P = 0.02), monocyte (P < 0.001) and lymphocyte (P < 0.001) count of NTD group were significantly increased compared to control group, but N/L (P = 0.02), L/M (P = 0.034) and N/M ratio (P < 0.001) were decreased. Conclusion: The interaction of maternal immune system with the abnormal fetus may change the compositions of peripheral blood WBC and sub-parameters. Some of these changes may increase the predictive sensitivity of STS test. Further prospective studies are needed to confirm these findings.