Pilot randomized clinical trial examining use of very low nicotine content cigarettes during pregnancy in the United States.

Objective: Randomized controlled trials have shown that reducing the nicotine content of cigarettes decreases the number of cigarettes smoked per day (CPD) without engendering compensatory smoking. The present study examined whether those effects extend to smoking during pregnancy.

Methods: Pregnant participants (≤25 weeks gestational age) in the U.S. with less than an Associate's degree and not planning to quit smoking were randomly assigned to smoke their usual brand (UB) cigarettes or very low nicotine content (VLNC) cigarettes (0.4 mg nicotine/g of tobacco) for 12 weeks. The primary outcome was total CPD at 12 weeks.

Results: Baseline characteristics did not differ between conditions (14 UB, 16 VLNC), but smoking-related variables were indicative of heavy smoking and moderate-high nicotine dependence. Mean (±SE) total CPD at 12 weeks among completers (11 UB, 12 VLNC) did not differ between conditions (18.4 ± 2.3 and 16.3 ± 2.6, respectively), nor did it vary over time. VLNC cigarette use did not lead to compensatory smoking, greater withdrawal or craving, or any severe or serious adverse events, and birth outcomes were within normal ranges on average.

Conclusions: Results suggest this sample of pregnant participants did not realize the same benefits of VLNC cigarettes that other not-pregnant samples have, although there was also no evidence of harm in the form of compensatory smoking or other adverse events. The sample's smoking characteristics suggest they were especially resistant to changing their smoking and it remains possible that those with more representative smoking patterns during pregnancy will respond to VLNC cigarettes as other populations have.

Clinicaltrials: govID:NCT04033237.