The aim was to establish whether the risk of trisomy 21 in women smokers un
dergoing triple test differs to women nonsmokers, whether increased smoking
changes the hormonal values, and if the cessation of smoking at the beginn
ing of pregnancy has any influence on the triple test. 1,854 pregnant women
were interviewed regarding their smoking habits at the time of the triple
test. They were divided into 5 groups: (a) nonsmokers; (b) smokers before p
regnancy; (c) 1-5 cigarettes; (d) 6-10; (e) 11 or more. MOM values of AFP,
E3 and beta-HCG and Down risk calculated by the triple test were compared w
ithin the 5 groups. Increasing smoking was associated with a reduction in M
OM values of beta-HCG.-Smokers were significantly less likely to be counsel
ed for karyotyping (cutoff level. 1:250) than nonsmokers. The values of wom
en who stopped smoking at the beginning of pregnancy were not different to
nonsmokers. The results suggest the benefits of inclusion of smoking habits
for the calculation of the triple test.