[Pregnancy and smoking: an opportunity to change behaviours]

Maternal smoking during pregnancy is related not only to perinatal adverse events but also to important postnatal problems. Smoking is very prevalent in women with several socio-demographic factors playing an important role.

To assess the frequency of smoking as well as mothers' change in behaviours during pregnancy. To identify socio-demographic factors associated to smoking and to assess women's knowledge and sources of information about adverse effects of smoking during pregnancy.

We started a cohort study between March and October 2003 at the Maternity, Hospital Santa Maria. After an informed consent the mothers in the post natal ward were asked to fill in a questionnaire.

Four hundred and seventy five mothers responded to the questionnaire and among them 30% were smokers before pregnancy. Thirty five percent stopped smoking during pregnancy and those who continued significantly reduced the number of cigarettes per day. Smoking was less prevalent in married women, with higher educational level and with stable employment (statistically significant correlations). Forty five percent of the mothers were misinformed or had no information about the adverse effects of smoking during pregnancy. Their main source of information were the media.

Smoking prevalence was high (30%) among the respondents but the pregnancy lowered the numbers of cigarettes per day. The percentage of misinformed mothers concerned about the adverse effects of smoking during pregnancy was high (45%), which also showed that doctors' role as a source of information was surpassed by the media. The study also brought to light the need for the health professionals to improve their competences in their role on prevention of smoking during pregnancy and the postnatal period.