Correspondence between self-reported and biochemical measures of smoking in opioid-dependent pregnant women

Aims: Smoking exacerbates adverse outcomes among opioiddependent pregnant women (e.g., a more severe neonatal abstinence syndrome in exposed neonates). Vermont birth certificate data for opioid-dependent pregnant women indicates a significant decrease in their self-reported smoking rate over the course of pregnancy, from a mean of 17.9 cigarettes per day (CPD) prior to pregnancy to 13.8, 10.9, and 9.7 in the first, second and third trimesters, respectively. This study examined self-reported smoking rate andbiochemicalmeasures of smoking to testwhether self-reported decreases in smokingwere paralleled by decreases in biochemical measures. Methods: Participants were 18 opioid-dependent pregnant women enrolled in clinical trials for smoking cessation. All women continued to smoke throughout their pregnancies. Self-reported CPD prior to pregnancy were collected at the Intake Assessment. CPD, breathCO, andurine cotininewere collected at intake, at a second assessment 1 month later (Early Pregnancy Assessment), and againat theendofpregnancy (≥28weeksgestation; LatePregnancy Assessment). Results: Like birth certificate data, self-reported smoking rates decreased from amean of 22.6 prior to pregnancy to 15.5 at intake. During pregnancy, self-reported CPD decreased significantly from 15.5, 7.5, and 9.0 at Intake and Early and Late Pregnancy Assessments, respectively (p< .001). However, parallel changes were not evident in biochemical measures of smoking. Mean CO was 13.3, 10.0, and 12.3ppm (p= .11) and mean urine cotinine was 1422.8, 1387.8, and 1294.1ng/ml (p= .71) at the three assessments. Conclusions: Discrepancies between self-report and biochemical measures may be explained by misrepresentation of self-reported smoking or reductions in CPD offset by changes in smoking topography (i.e., compensatory smoking). Further research is needed to understand changes in smoking among opioid-dependent pregnant women. Financial support:NICHDR01HD075669, NIDAR01DA014028 and R01 DA031928, and FDA/NIDA P50 DA036114.