Exposure to tobacco smoke both prenatally and after birth is associated with measurable harmful effects including a greater risk of developing asthma-like symptoms in early childhood. However, evidence of increased risk of allergic diseases is uncertain77, 78. Distinguishing the independent contributions of prenatal and postnatal maternal smoking is problematic79. However, studies of lung function immediately after birth have shown that maternal smoking during pregnancy has an influence on lung development37. Furthermore, infants of smoking mothers are 4 times more likely to develop wheezing illnesses in the first year of life80. In contrast, there is little evidence (based on metaanalysis) that maternal smoking during pregnancy has an effect on allergic sensitization78. Exposure to environmental tobacco.
