A pregnancy is a special period for both the mother and the child. Pregnant women can promote health and prevent several adverse health outcomes through healthy lifestyle habits. This systematic review examines the effect of one extra counselling session to women about healthy lifestyles within the first trimester. We searched several databases for different types of effect studies.

We found only two relevant studies. In these studies, the women received extra smoking cessation counselling once (10-15 minutes) during the first trimester. One of the studies also included recent ex-smokers. The control groups received standard antenatal care, which included basic smoking cessation advice.

We found that:

• One extra smoking cessation session within the first trimester for recent ex-smokers may increase the proportion who are abstinent at birth.
• The evidence is too uncertain to conclude whether one extra smoking cessation session within the first trimester alter the proportion of pregnant smokers who are abstinent women at birth and 6 months later.
• We lack information to conclude whether one counselling session about healthy lifestyles within the first trimester influences alcohol consumption, dietary habits or physical activity.