[Smoking, fetal pulmonary development and lung disease in children].

Prenatal exposure to tobacco smoke is associated with a significant increase in respiratory symptoms and a decrease in lung function in children. Epidemiological studies have demonstrated that tobacco smoke exposure represents one of the most important respiratory risk factors in childhood. Nicotine crosses the placenta and activates the nicotinic receptors which are present in a wide range of lung cells during the prenatal period. In utero tobacco exposure is responsible for an increase in alveolar volumes and a decrease in airway walls caliber, which explains the decrease in airflow that is observed during the first days of life in infants of smoking mothers. These structural and functional disturbances explain why these infants are more susceptible to respiratory irritants. The alterations in ventilatory control induced by prenatal exposure to nicotine explain the link between tobacco smoke exposure and the sudden infant death syndrome. This underlines the importance of adequate information and preventative measures to decrease this major and avoidable cause of respiratory morbidity and mortality in infants.