Erythrocyte count and indices during normal pregnancy of non-smoking and smoking women.

OBJECTIVE

To compare the erythrocyte count and the erythrocyte indices of smoking and non-smoking women at different stages of normal gestation.

STUDY DESIGN

In 247 non-smoking and 123 smoking healthy pregnant women the erythrocyte count and indices were compared at four different stages of pregnancy: 0-10, 10-20, 21-30 and 31-40 weeks. Exclusion criteria were a diastolic pressure > or = 90 mmHg, an endocrine disease or a coagulation disorder. A woman was considered a smoker if she smoked 4 or more cigarettes/day. Blood samples were run on the Sysmex NE-8000.

RESULTS

The erythrocyte count was significantly lower in smokers than in non-smokers (3.86 T/l versus 3.96 T/l in the last 10 weeks). Comparing the erythrocyte count during the beginning and the end of pregnancy there were significant lower values in both groups (4.32 T/l to 3.96 T/l in the non-smoking and 4.24 T/l to 3.86 T/l in the smoking group). The differences in the median Hb and Ht levels were neglectable. The MCV was significantly higher in women who smoked, as was the MCH (MCV 91 fl and MCH 1.90 fmol in the non-smoking versus MCV 94 fl and MCH 1.95 fmol in the smoking group in the last 10 weeks).

CONCLUSION

Smoking in pregnancy leads to a lower erythrocyte count and a higher MCV which might create a hypoxic condition of the fetus.