Comparison of self-reported smoking and urinary cotinine levels in a rural pregnant population

Objectives: (a) to assess the accuracy of self-reported smoking status in pregnant women from rural and small metropolitan statistical areas who stated they were smokers at the onset of pregnancy, (b) to compare the characteristics of these women who self-reported a nonsmoker status at the first prenatal visit with those who reported a smoker status, and (c) to determine the characteristics that predict self-reported smoking status and positive/negative urinary cotinine assays. Setting: Seven private obstetric offices serving rural and small metropolitan statistical areas in upstate New York. Participants: A convenience sample of 94 pregnant women who stated they were smokers at the onset of their pregnancies. Their mean age was 23 years and mean level of education was 11.9 years; 95% were White, 65% were single, and 65% were Medicaid-funded. Design: Descriptive correlational design. At the first prenatal visit, the sensitivity and specificity of smoking and nonsmoking status were determined by comparing self-reports of smoking status with urinary cotinine assays. Data were also analyzed for relationships among demographic variables and for predictors of smoking status and urinary cotinine. Results: The discordance rate between self-reports of smoking status and urinary cotinine assays at the first prenatal visit for the total sample was 16.6%, significant at p <.001, chi-square = 27.80, df = 1. Based on biochemical assays of > 200 ng/ml of cotinine indicating active smoking, 34.7% of women who denied smoking (specificity of 65.3%) and 10.4% of women who stated that they smoked (sensitivity of 89.5%) inaccurately reported their status (significant at p <.001). The number of cigarettes smoked per day was positively correlated with age, gravidity, parity; and number of smokers in the household. Gravidity and the number of smokers in the household were significant predictors of positive self-report of smoking status and of positive urinary cotinine assay. Conclusion: These results substantiate the unreliability of self-report on smoking status in the pregnant population and in women who are recent quitters. Such findings have implications for clinical practice, such as (a) changes are necessary in how the prenatal interview assesses past and present tobacco use, (b) pregnant smokers who are multigravidae and who live with other smokers need more tailored interventions, and (c) more research is needed on how self-report can be ethically and efficiently validated. JOGNN, 33, 306-311; 2004.