The Collection and Analysis of Carbon Monoxide Levels as an Indirect Measure of Smoke Exposure in Pregnant Adolescents at a Multidisciplinary Teen Obstetrics Clinic

Abstract

Study ObjectiveIn this study we aimed to collect and analyze CO levels as an indirect measure of smoke exposure in pregnant adolescents. Design, Setting, and ParticipantsParticipants included pregnant adolescents who received antenatal care over 18 months (2012-2013) at the Multidisciplinary Teen Obstetrics Clinic at a tertiary-care hospital in Southeastern Ontario. InterventionsThe CO breath test is a noninvasive method that is used to assess smoke exposure, in which nonsmokers have levels of 0-6 ppm, and levels of 7-10, 11-20 and more than 20 ppm are consistent with light, typical, and heavy smokers, respectively. Expired CO, smoking status, cigarette number, and home secondhand smoke exposure were documented at 3 clinic visits. Main Outcome MeasuresTo determine mean CO levels as a measure of smoke exposure and prevalence of secondhand smoke exposure. ResultsThe mean age of participants was 17.6 years. CO means (ppm) across 3 visits were 6.0, 5.9, and 4.8. Sixty-two percent of patients were self-reported nonsmokers, 38% were self-reported smokers (n = 93). CO means (standard error of the mean) were consistently different for nonsmokers vs smokers at visits 1 to 3, respectively: 2.9 (0.79) vs 9.7 (1.8); 3.0 (0.71) vs 12.9 (2.2), and 2.4 (0.71) vs 8.8 (1.5; P < .01, t test; n = 91). Of patient's highest CO (COmax), 62%, 9%, 15%, and 12% had levels of 6 or less, 7-10, 11-20, and greater than 20, respectively. Eighty-four percent of pregnant adolescents had home secondhand smoke exposure, which included 40% of nonsmokers and 100% of smokers (n = 57). Although most nonsmokers had a COmax of 6 or fewer ppm, 56% of smokers had COmax greater than 10 ppm (P < .05, χ2). ConclusionEmphasis on smoking cessation is imperative in pregnant adolescents and should particularly target partners and families, because secondhand smoke exposure was very prevalent.