Electronic cigarettes versus nicotine patches for smoking cessation in pregnancy: a randomized controlled trial


Nicotine replacement therapy, in the form of nicotine patches, is commonly offered to pregnant women who smoke to help them to stop smoking, but this approach has limited efficacy in this population.

Electronic cigarettes (e-cigarettes) are also used by pregnant women who smoke but their safety and efficacy in pregnancy are unknown. Here, we report the results of a randomized controlled trial in 1,140 participants comparing refillable e-cigarettes with nicotine patches.

Pregnant women who smoked were randomized to e-cigarettes (n = 569) or nicotine patches (n = 571). In the unadjusted analysis of the primary outcome, validated prolonged quit rates at the end of pregnancy in the two study arms were not significantly different (6.8% versus 4.4% in the e-cigarette and patch arms, respectively; relative risk (RR) = 1.55, 95%CI: 0.95–2.53, P = 0.08). However, some participants in the nicotine patch group also used e-cigarettes during the study. In a pre-specified sensitivity analysis excluding abstinent participants who used non-allocated products, e-cigarettes were more effective than patches (6.8% versus 3.6%; RR = 1.93, 95%CI: 1.14–3.26, P = 0.02).

Safety outcomes included adverse events and maternal and birth outcomes. The safety profile was found to be similar for both study products, however, low birthweight (<2,500 g) was less frequent in the e-cigarette arm (14.8% versus 9.6%; RR = 0.65, 95%CI: 0.47–0.90, P = 0.01). Other adverse events and birth outcomes were similar in the two study arms. E-cigarettes might help women who are pregnant to stop smoking, and their safety for use in pregnancy is similar to that of nicotine patches. ISRCTN62025374.


Smoking in pregnancy increases the risk of adverse birth outcomes such as low birthweight, placental abruption, preterm birth, miscarriage and neonatal or sudden infant death1,2,3,4. The need to identify stop-smoking interventions that help pregnant women who smoke is made even more urgent by the fact that the link between smoking and socioeconomic disadvantage is particularly strong in women who are pregnant5.

To date, two stop-smoking medications have been tested with pregnant women who smoke. Nine placebo-controlled trials evaluated the efficacy of nicotine replacement therapy (NRT)6,7,8,9,10,11,12,13,14 and two trials evaluated bupropion15,16, showing only limited effects for NRT and no effect for bupropion17. These results could be due to low treatment adherence and, in the case of NRT, also to limited nicotine delivery. Nicotine is metabolized faster in pregnant women who smoke than in women who smoke and are not pregnant, and standard NRT dosing might be too low8,18,19,20,21.

Electronic cigarettes (e-cigarettes) are devices that deliver nicotine and flavorants in an aerosol that is created by heating propylene glycol and vegetable glycerol22. E-cigarettes can be seen as a form of NRT, although they are a consumer rather than pharmaceutical product. E-cigarettes may have several potential advantages over traditional NRT products, such as nicotine patches and gum, in that they enable individuals who smoke to titrate nicotine intake to their needs, select flavors they like, and retain a degree of enjoyment that they previously obtained from smoking22,23,24,25,26. E-cigarettes are more popular than traditional NRT products among people who are trying to stop smoking27,28, and the first few trials comparing the two treatments in non-pregnant participants suggest that e-cigarette are more effective than NRT for aiding smoking cessation29,30. The use of e-cigarettes as a quitting aid has also increased in pregnant women who smoke31,32,33, although the efficacy and safety of such use is unknown.

The use of e-cigarettes in women who are pregnant raises similar concerns about the potential harmful effects of nicotine on the developing fetus to those regarding the use of nicotine patches or chewing gum. The use of medicinal NRT products to help pregnant women to stop smoking is approved in a number of countries because although NRT contains nicotine, tobacco smoke also contains many other toxins with documented teratogenic effects34,35,36,37,38,39. The evidence that nicotine is teratogenic is also only available from animal studies36. It is currently not clear whether nicotine has detrimental effects in pregnancy when used at doses consumed by humans who smoke. Two recent reviews concluded that existing data do not provide clear evidence on whether the use of NRT during pregnancy is harmful to the fetus1,40. Given that the issue has not been definitively settled, and given that e-cigarette aerosol contains other chemicals in addition to nicotine41, objective data on pregnancy outcomes in women who switch from smoking to e-cigarette use are urgently needed.

Here, we compare the efficacy and safety of e-cigarette and NRT patches when used to help pregnant women who smoke to attain prolonged abstinence from smoking in a randomized controlled trial.


Recruitment took place between 11 January 2018 and 7 November 2019. Participants were recruited from 23 hospital sites across England and one National Health Service Stop Smoking Service in Scotland. Participant characteristics are listed in Table 1. Participants had a median age of 27 years, smoked 10 cigarettes per day, and were on average 15.7 weeks pregnant. The profiles of participants in the two study arms were similar. Figure 1 shows the flow of participants through the trial. We were able to establish self-reported smoking status at the end of pregnancy, via direct contact or hospital records, in 531 (93%) and 516 (91%) participants in the e-cigarette and NRT arms, respectively.

Read full article here.

Peter Hajek, et al. – Nature Medicine – Outlet – 2022-05-16.

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