Further evidence for the effect of passive smoking on neonates.

From 518 couples with a 1 month old baby, information was obtained on the couple's smoking habit, social class, age of mother, parity, alcohol consumption during pregnancy and respiratory symptoms of the baby. Allowing for these factors, a multivariate analysis revealed that, even allowing for mother's smoking habit, babies whose father smoked were lighter at birth by an average of 113 g (95% CI 8-216 g) and this effect was unchanged at 1 month (112 g, 95% CI 0-224 g). Babies whose mothers smoked were twice as likely to have a cough (Relative Risk = 2.0, 95% CI 1.05-3.68), than those whose mothers did not, but we failed to find a significant association with the father's smoking habit.