White blood cell count as a predictor of the severity of sickle cell disease during pregnancy

Objective: Increasing epidemiological evidence implicates leukocytosis as a major risk factor for poor outcome in non-pregnant sickle cell disease (SCD) patients. The aim of this study was to investigate whether steady-state white blood cell (WBC) count can predict SCD-related problems in pregnancy. Design: Retrospective observational study of 40 SCD pregnant women who had their antenatal care at Guy's & St Thomas' NHS Trust, London. Twenty-six women developed clinical complications related to SCD during their pregnancy (painful crisis, chest symptoms, infections. severe anaemia requiring blood transfusion, pre-eclampsia, and/or thromboembolism) and 14 remained asymptomatic. The steady-state leukocyte counts early in pregnancy were compared between the two groups and receiver operator characteristics (ROC) curve was plotted for different values of WBC. Results: Compared to asymptomatic patients, women who developed SCD-related complications had significantly higher total WBC count [ 11.2 x 10(9) L-1 (SD 3.22) versus 8 x 10(9) L-1 (2.8), p < 0.0 1], higher lymphocyte count [3 x 109 L-1 (1.62) versus 1.6 x 109 L-1 (0.65), p < 0.0 1] and higher monocyte count [0.8 x 10(9) L-1 (0.47) versus 0.4 x 10(9) L-1 (0.2 1), p < 0.01]. The neutrophil count showed a similar trend but the difference did not reach statistical significance [6.6 x 10(9) L-1 (2.29) versus 5.7 x 10(9) L-1 (2.15), p = 0.22]. The area under the ROC curve was 74% (95% CI: 56-92). Conclusion: WBC count early in pregnancy was significantly higher in women who subsequently developed clinical problems related to SCD. The WBC may be used as a predictor of the severity of SCD in pregnancy. (C) 2006 Published by Elsevier Ireland Ltd.