Smoking and carbon monoxide levels during pregnancy.

Self-reports of smoking status and breath tests for carbon monoxide were collected in prenatal outpatients. The breath test for carbon monoxide appeared to be a valid and specific measure of smoking status during pregnancy. Of the 179 patients surveyed, 99 reported they had smoked during the present pregnancy. Nineteen of the smokers reported they had quit during the present pregnancy and 46 reported that they smoked fewer cigarettes than at the beginning of their pregnancy. Most of the quitters and reducers stated that they had stopped or reduced their intake early in pregnancy and for pregnancy-related reasons; however, neither parity, nausea or vomiting, marital status, nor requests of physicians or family were associated with higher rates of smoking cessation or reduction. Most of the pregnant smokers were interested in stopping smoking, but few attended a free treatment program.