Objective: The purpose of this study was to assess whether pregnant smokers have the same nicotine intake from cigarettes as a general population of smokers and whether the known lower daily cigarette consumption among pregnant smokers is associated with higher nicotine intake among pregnant smokers.
Method: The study was a cross-sectional comparison of pregnant smokers and a general population of smokers in smoking cessation clinics. Participants were treatment-seeking pregnant (n = 476), nonpregnant female (n = 116), and male (n = 195) smokers who participated in two independent smoking cessation trials. Nicotine intake was measured as saliva cotinine/ cigarette/kg body weight ratio.
Results: The mean saliva cotinine (μg/L)/ cigarette/kg body weight (0.21, SD = 0.15) of pregnant smokers was similar to that of nonpregnant female smokers (0.24, SD = 0.14) and higher than that of male smokers (0.18, SD = 0.12, p = .002) despite a substantially lower number of cigarettes per day (pregnant smokers: 12, SD = 6; nonpregnant female smokers: 26.6, SD = 11.7; male smokers: 23.5, SD = 9.5, p < .001). Among pregnant smokers, saliva cotinine, as expected, increased in parallel with the number of cigarettes per day, but nicotine intake (cotinine/cigarette/kg body weight) was inversely associated with daily cigarette consumption (p < .001). No association between cigarettes per day and nicotine intake was observed in male and nonpregnant female smokers (p = .43).
Conclusions: This secondary analysis showed that pregnant smokers' nicotine intake was similar to that of a general population of smokers despite a lower cigarette consumption rate. Among pregnant smokers, lower daily cigarette consumption was associated with higher nicotine intake from cigarettes, suggesting compensatory smoking.