Maternal passive smoking and fetal serum thiocyanate levels.

Passive smoking, exposure of the nonsmoker to air contaminated with tobacco smoke, has been reported to have several adverse consequences for health. However, its effects on the fetus are unknown. Detailed smoking histories and fetal SCN (thiocyanate) levels were obtained in 107 low-risk pregnancies in order to evaluate fetal exposure to this metabolic byproduct of tobacco smoke. Among nonsmokers, fetal SCN levels were increased in association with passive smoking in the home (p less than 0.05). Significant differences in clinical characteristics were associated with passive smoking, but none of these differences were accounted for a significant increase in fetal SCN levels. These findings suggest that maternal passive smoking exposes the fetus to SCN, which is reported to be an effective biochemical marker of overall exposure to smoking, and which is known to be toxic in higher doses.