RESUMO
This study aimed to evaluate the effect of variable degrees of environmental exposure to tobacco smoke during pregnancy in 152 nonsmoking pregnant women. Based on a questionnaire fulfilled by the parents, newborns were classified into five groups depending on degree of exposure. Birth weight of babies born to mothers significantly exposed to tobacco smoke was 230 grams less than those babies born to non- exposed mothers. Also, there was a difference of 176 grams in birth weight between babies born to mothers significantly exposed to tobacco smoke and babies born to mothers occasionally exposed to tobacco smoke. It was concluded that passive smoking has a negative influence on intrauterine fetal growth and duration of exposure is more important than intensity of exposure