Comparison of prenatal self-report of tobacco use to direct measurement of umbilical cord cotinine

OBJECTIVE: This study compared maternal self-reports of prenatal tobacco product use with biochemically confirmed cotinine in umbilical cord tissue in newborns exposed to opioids in utero and unexposed controls. STUDY DESIGN: Secondary data analysis on 179 pregnant women and newborns. Chi-square and t-tests were used to compare sociodemographic factors of those who did and did not self-report tobacco use. RESULTS: Mean (SD) maternal age was 29.5 years (5.0); 85.2% had public insurance, and 92 (51.4%) took opioids prenatally. Ninety-five (53.1%) mothers self-reported prenatal tobacco product and/or e-cigarette use, with cord cotinine detected in 98.9%. Of the 84 reporting no use, cotinine detection was 34.5%, resulting in moderate agreement (Gwet's AC1 = 0.68 (0.571, 0.788), p < 0.001). Of those reporting no use, 27 (32.9%) had cotinine detected (p = 0.038). CONCLUSIONS: Biochemically verified cotinine detection was much higher than maternal self-reports of prenatal tobacco use. Inquiring about household and community smoke exposure may help inform optimal care.