Leukocytosis and tobacco use during pregnancy

Factors such as tobacco and other toxic substance use, obesity, associated comorbidity, and intercurrent infections can cause a proinflammatory state and modify analytical parameters. The objective of this study is to identify smoking-induced leukocytosis in pregnant women across all three trimesters of pregnancy to aid in their clinical assessment.

Demographic and analytical data were reviewed for 300 pregnant women included in the WOMAP trial during the three trimesters of pregnancy, evaluating white blood cell counts, neutrophil and lymphocyte percentages, and hemoglobin and hematocrit values. Leukocytosis association with smoking was assessed via logistic regression.

The sample had a mean age of 31.60 ± 6.00 years, with a mean body mass index of 24.70 ± 5.35 kg/m² and 16.00% obesity (n = 48); 47.33% (n = 142) of pregnant women were smokers, and 60.70%(n = 182) were patients with co-occurring mental health and alcohol and/or tobacco use problems (dual pathology). Pregnant women who smoked had higher white blood cell counts in all trimesters compared to non-smokers (P = 0.001). The percentage of leukocytosis was higher in the group of smokers. For white blood cells ≥10 500/μL, the difference was statistically significant in all three trimesters (P = 0.014, P = 0.0001, and P = 0.007, respectively), while for leukocytosis ≥15 000/μL, the difference was significant in the third trimester (P = 0.0001). When considering other proinflammatory factors (obesity and dual pathology), the association between leukocytosis and tobacco held (P < 0.01).

Tobacco use during pregnancy was associated with elevated white blood cell counts and leukocytosis in all trimesters. In pregnant women with leukocytosis, smoking history should be reviewed, and smoking cessation should be encouraged.