Authors' objectives: Some pregnant smokers try e-cigarettes, but effectiveness and safety of such use are unknown. To compare effectiveness and safety of nicotine patches and e-cigarettes in pregnancy. Pregnant smokers in the UK are routinely recommended nicotine patches (NPs), though their efficacy in this population is limited. Some pregnant smokers try spontaneously to reduce or stop smoking with the help of e-cigarettes (ECs), but safety and efficacy of such use are unknown. We compared NPs and ECs in a pragmatic multi-centre randomised controlled trial.

Authors' results and conclusions: Only 55% of self-reported abstainers mailed back useable saliva samples. Due to this, validated sustained abstinence rates were low (6.8% vs. 4.4% in the e-cigarettes and nicotine patches arms, respectively, risk ratio = 1.55, 95% confidence interval 0.95 to 2.53; Bayes factor = 2.7). In a pre-specified sensitivity analysis that excluded abstainers using non-allocated products, the difference became significant (6.8% vs. 3.6%, risk ratio = 1.93, 95% confidence interval 1.14 to 3.26; Bayes factor = 10). Almost a third of the sample did not set a target quit date and the uptake of support calls was low, as was the initial product use. At end of pregnancy, 33.8% versus 5.6% of participants were using their allocated product in the e-cigarettes versus nicotine patches arm (risk ratio = 6.01, 95% confidence interval 4.21 to 8.58). Regular use of e-cigarettes in the nicotine patches arm was more common than use of nicotine replacement products in the e-cigarette arm (17.8% vs. 2.8%). Rates of adverse events and adverse birth outcomes were similar in the two study arms, apart from participants in the e-cigarette arm having fewer infants with low birthweight (

Authors' methods: A pragmatic multi-centre randomised controlled trial. Twenty-three hospitals across England, and a Stop Smoking Service in Scotland. One thousand one hundred and forty pregnant daily smokers (12–24 weeks’ gestation) motivated to stop smoking, with no strong preference for using nicotine patches or e-cigarettes. Participants in the e-cigarette arm were posted a refillable e-cigarette device with two 10 ml bottles of tobacco-flavoured e-liquid (18 mg nicotine). Participants in the nicotine patches arm were posted a 2-week supply of 15 mg/16-hour nicotine patches. Supplies were provided for up to 8 weeks. Participants sourced further supplies themselves as needed. Participants in both arms received support calls prior to their target quit date, on the quit date, and weekly for the next 4 weeks. Low rates of validation reduced the study power. A substantial proportion of participants did not use the support on offer sufficiently to test its benefits. Sample size may have been too small to detect differences in less frequent adverse effects. Twenty-three hospital sites across England, and one NHS Stop Smoking Service (SSS) in Scotland. One thousand one hundred and forty pregnant daily smokers (12–24 weeks’ gestation) motivated to stop smoking, with no strong preference for using NPs or ECs. Participants in the EC arm were posted a refillable EC device with two 10 ml bottles of tobacco-flavoured e-liquid (18 mg nicotine). Participants in the NP arm were posted a 2-week supply of 15 mg/16-hour NPs. Further supplies of both products were provided for up to 8 weeks, with participants encouraged to source further supplies themselves as needed. Participants in both arms received support calls prior to their target quit date (TQD), on the date, and weekly for the next 4 weeks. The primary outcome was biochemically validated prolonged abstinence from smoking at the end of pregnancy (EOP). Three pre-specified sensitivity analyses were conducted: (1) a per-protocol analysis that excluded participants who did not start product use or never established contact with the study team; (2) multiple imputation of missing data; and (3) an analysis that excluded abstainers who were regularly using non-allocated products. Participants lost to follow-up or not providing biochemical validation were included as non-abstainers. Secondary outcomes included self-reported abstinence at different time points, treatment adherence and safety outcomes. Return rates of posted saliva samples were low, resulting in low validated quit rates and reduced power to detect a difference between the two study arms. The 2019 outbreak of a lung disease in young vapers in the USA caused by illicit marijuana products but widely reported as due to nicotine vaping led some participants to stop using ECs and return to smoking. Treatment adherence was low, with a substantial proportion of participants not using the help on offer sufficiently enough to test its benefits. The finding that nicotine use does not affect birthweight only concerns nicotine use in late pregnancy, because all participants smoked in early pregnancy.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/15/57/85

Year Published: 2023

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/AGTH6901

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/AGTH6901

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk