We attempted to address these issues using data from a large randomized trial conducted in three states (Colorado, Maryland, and Missouri) from 1987-1991. This study was meant to evaluate the effects of low-intensity smoking cessation counseling on quitting behavior.

There were 5,572 pregnant, self-reported smokers enrolled in the study. For our analysis, we restricted the original study sample to women of white or black race who delivered singleton, term (> 37 weeks gestation) infants of a plausible birth weight.