[The influence of smoking on fertility, pregnancy and lactation].

OBJECTIVE: To decribe the influence of smoking on different phases of the reproductive process, fecundation, pregnancy and lactation, drawing special attention to the mechanisms of action of the main toxic components found in cigarettes. To suggest prophylactic measures for environmental control and how to reduce childreńs exposure to tobacco smoke. METHODS: Nonsystematic literature review using MEDLINE database. RESULTS: Smoking has a negative effect on different phases of the reproduction process, by direct action of main toxic components, nicotine and carbon monoxide. Smoking reduces fertility, compromises the length of gestation and infant birthweight. Smoking mothers also have reduced breast milk production and shorter lactation, which affects infant weight gain through unclear mechanisms in which prolactin may probably be involved. CONCLUSIONS: Smoking compromises reproductive function quality in different phases, acting mainly on intrauterine and extrauterine development of infants. Since during pregnancy and lactation women are in closer contact with health professionals, antismoking campaigns should be especially addressed to this period.