Maternal cigarette smoking is one of the most hazardous environmental exposures during pregnancy and understanding its health consequences is complicated by method of ascertainment of exposure. There are two primary methods of assessing smoking behavior: self-report and biological assay. Few studies have characterized the potential discrepancy between these two methods.METHODS:
Subjects participated in prospective observational studies of the perinatal course of mental illness at the Emory Women's Mental Health Program. Participants' tobacco exposure was ascertained by weekly self-report and assay of urine levels of nicotine and cotinine at one or more time points during pregnancy. We compared self-report and objective measures collected in the same week to determine if a patient “under-reported” (denied) smoking during the pregnancy.RESULTS:
In a sample of 804 pregnant women, relying upon urine assay, the overall prevalence of active and passive smoking was 10.3% and 0.6%, respectively. By self-report, the prevalence of smoking was 14.8%, 8.6% and 8.0% in the first, second and third trimesters, respectively. The prevalence of under-reporting smoking during pregnancy was overall 2.4%, and among 83 active smokers confirmed by positive biomarkers, 23% denied cigarette smoking on one or more occasions.CONCLUSION:
In our study, approximately one in four pregnant women denied cigarette smoking when biomarkers identified them as current smokers. Though the sample consists of women with a psychiatric history, this suggests that self-report of cigarette exposure may not be sufficient to identify at-risk pregnancies in a broader population. Efforts should be aimed at decreasing barriers to patient disclosure.