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Clinical Obstetrics

Poster Session 4

(1052) Smoking Reduction in Gravid Patients with Substance Use Disorders (SIGS): A Randomized Controlled Trial

Wednesday, February 14, 2024
1:00 PM – 2:30 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective: To determine if measuring exhaled carbon monoxide (eCO) at prenatal visits (PNV) is associated with cigarette smoking cessation or reduction as estimated by eCO.

Study Design: Single-center, parallel randomized trial including pregnant individuals 14-45 years old < 24 weeks gestational age (GA) who self-reported smoking ≥10 cigarettes/day. Multiples, fetal growth restriction (FGR), anomalies/aneuploidy, demise, or e-cigarette use were exclusions. All participants measured eCO at PNV but were randomized 1:1 to either eCO disclosure or no disclosure (control). Primary outcome was prevalence of smoking ≥10 cigarettes/day at final measurement (FM) per eCO. With 90% power and 2-sided α of 0.05, a sample size of 74 was estimated to detect a 50% reduction in smoking ≥10 cigarettes/day from a rate of 90%. Secondary outcomes were self-reported smoking and average # of cigarettes smoked/day per eCO, average %fetal carboxyhemoglobin (%FCH) at FM, FGR, GA at delivery, birthweight (BW), and Apgars.

Results:

From 2/2021 to 2/2023, 74 patients were randomized. eCO values at randomization were higher in the intervention group (15.4±8.8 vs 11.3±5.6, p=0.02). Thirty in the intervention and 32 in the control arm had delivery data available for analysis. Prevalence of smoking ≥10 cigarettes/day at FM per eCO was not different (73% vs 50%, p=0.06). Prevalence of self-reported ≥10 cigarettes/day (39% vs 52%, p=0.30), average # of self-reported cigarettes/day (8.1±8.5 vs 7.8±5.2, p=0.90), average # of cigarettes per eCO (18.3±9.4 vs 14.6±9.6; p=0.12), and average %FCH (4.3±4.8 vs 2.6±1.9, p=0.08), all at FM, were not different between the intervention and control groups, respectively (Table). Clinical outcomes including FGR (3% vs 0%, p=0.49), GA at delivery (35±5.8 vs 36±4.0, p=0.29), BW (2396±1129 vs 2785±722g p=0.27) and 5-minute Apgars (7±3 vs 8±2, p=0.73) were not different. Despite this, most participants in the intervention and control arms (83% vs 60%, p=0.14) report planning future device use.

Conclusion: Exhaled carbon monoxide monitoring in pregnancy did not improve smoking cessation or clinical outcomes.