Maternal smoking, birth weight, and infant health

Recent research into the implications of birth weight for infant health, and the implications of smoking during pregnancy for birth weight, may be plagued with omitted variable bias. In this study, two unique British longitudinal data sets on children and their mothers are used to address this issue. Cross sectional and panel estimates which exploit within-sibling differences in data suggest that improvements in birth weight will produce healthier children especially among women at risk of delivering low birth weight infants. Furthermore, the fixed estimates imply the benefits of smoking cessation among pregnant women are greatly exaggerated by the well-documented cross-sectional estimates. The results suggest that smoking during pregnancy reduces birth weight on average by 100 grams