Smoking substantially inhibits the activities of both monamine oxidase (MAO) A and B enzymes.

Aims of this study: to compare MAO activities and nicotine and cotinine in peripheral blood of smoking and nonsmoking pregnant women, in their placenta and in cord blood and relate them with the behavior of their newborns being observed during 48 hours after birth.

40 pregnant smoking and 40 pregnant nonsmoking women will be included at the end of the 2nd trimester.

Assessments: smoking characteristics, plasma cotinine, DHPG, DOPAC, 5HIAA concentrations reflecting MAOA activity and platelet MAOB activity will be measured just after inclusion (end of 2nd trimester), just before delivery in venous maternal blood and just after delivery in cord blood.

The newborns' behavior (wellbeing) will be assessed every 8 hour after birth for 2 days.

Comparisons will be made between smoking and nonsmoking women and their newborns.

Inclusion Criteria:

• pregnancy of 5 or 6 months
• nonsmokers: lifetime smoking of less than 100 cigarettes; smokers: unable to stop smoking during the first 3 months of pregnancy; smoking at least 10 cigarettes/day.

Exclusion Criteria:

• pathological pregnancies
• opioid dependence; alcoholism.
• chronic psychiatric, hematological, neurological disorders
• eclampsia
• chronic antidepressant or neuroleptic treatment
• current nicotine replacement therapies

pregnant smoking or not smoking women