Fetal and neonatal events in the development of allergy

In recent years, events occurring in the prenatal period and early infancy have been recognized as playing important roles in the risk for and development of allergy. Possible influences include factors such as genetic predisposition; in utero exposures to cigarette smoke, allergens, and immune modulators; postnatal passive smoke exposure; feeding practices; and infections in early infancy. Each of these may have different effects on the processes of allergen sensitization and the development of allergic disease.