Smoking and carboxyhaemoglobin concentrations in mothers and their newborn infants.

There were significantly higher carboxyhaemoglobin blood concentrations in mothers who were smokers than those in mothers who were non-smokers and ex-smokers (P less than 0.001). Carboxyhaemoglobin blood concentrations in newborn infants were nearly one-third higher than those in their mothers. Newborn infants from mothers who smoked had lower birthweights and higher carboxyhaemoglobin blood concentrations than those in newborn infants from mothers who were non-smokers and ex-smokers. Smoking during pregnancy increases the risk for a baby. This finding shows the importance of women giving up smoking during pregnancy.