Introduction: The effects of smoking on the organism are being constantly evaluated and discussed, due to toxicological risk of nicotine, particularly for pregnant women. Objective: Identify the cigarette consumption habit in women, before and/or during gestation, and its possible effects on the fetus and/or the newborn, as well as other factors that might influence gestational development and, consequently, the baby. Methods: During three months, the AA conducted a field research on a non-probabilistic sample of 62 pregnant women assisted in a Health Center of São Paulo, during the prenatal and postnatal phases, respectively, from the 6th month of pregnancy, and after the birth; these patients were properly advised and only took part in this research after signing a Free and Explained Consent Term, which made the collection of information possible, based on a previous validated questionnaire. Results: Among the pregnant women researched, we detected 10 (16%) smokers, 14 (23%) ex-smokers and 38 (61%) non-smokers. Among smoking women, there was a higher incidence of premature birth and prolonged gestation, as well as underweight and small newborns. Among the ex-smokers, there was a higher incidence of spontaneous miscarriages and newborns with cardio-respiratory problems. Conclusion: In comparison with non-smokers, the cigarette effects on smoking and ex-smoking women were toxicologically more relevant, although a possible interaction of nicotine (and other cigarette components) with environmental factors cannot be discarded.