[The effect of pregnancy on the consumption of tobacco and alcohol].

Objectives: To determine if the knowledge of pregnancy modifies smoking and drinking habits and if some socio-demographic variables exert any influence in these changes.
Design: Descriptive observational study with a sectional design (prevalence study).
Setting: Obstetric service of a Spanish general hospital, and also three private centres in the same area.
Participants: 271 women (mean age of 29 years) under 14 weeks of gestation (mean of 9 weeks) who attended to their first gynaecology visit and accepted to participate in the study.
Interventions: By means of direct interview to women, investigators filled a questionnaire with demographic characteristics, obstetric data, smoking and drinking habits and changes in these habits as a response to their pregnancy were also recorded.
Measurements and Main Results: Almost eighty percent of them planned their pregnancy, and 14.8% were using some contraceptive method when they became pregnant. Before learning of their pregnancy most of the women smoked cigarettes (53.5%), and a low proportion consumed alcohol at meals (20.3%) or between meals (10.7%). After knowledge of their pregnancy, 46.9% of smokers, 56.4% of drinkers during meals, and 86.2% of drinkers between meals, stopped these habits. Those women who smoked fewer cigarettes showed a higher capacity to stop consumption. It was also observed that those who gave up drinking at meals were those who drank less alcohol and who had no university degree.
Conclusions: A high prevalence of smoking among fertile women was observed, although an important proportion of them stopped this consumption after learning about their pregnancy. This change was less frequent among the heavy smokers. Consequently, the establishment of specific programs for encouraging abstinence of alcohol and cigarette consumption in several population groups as described, could be recommended.