Leucocyte count and leucocyte differential in smoking and non-smoking females during pregnancy.

The total leucocyte count was studied in 194 smoking and 518 non-smoking healthy pregnant women. Smoking in pregnancy appeared to have an additive enhancing effect on the already known total leucocyte increase in pregnancy. The leucocyte differential in 105 smoking and 288 non-smoking pregnant women showed that the eosinophil and basophil count was not involved in the white blood cell shift. The rise of the total leucocyte count was mainly due to an increase of neutrophils, monocytes and lymphocytes. The leucocytosis in the smoking pregnant women was dose-related: significant upward jumps of the percentages of leucocytosis were observed between 12 and 15 cigarettes/day as well as between 19 and 20 cigarettes/day. Further investigation as to the relevance of these observations for pregnancy and fetal well being has to be conducted.