Offering shopping vouchers to pregnant women as an incentive to quit smoking showed promising results, a study found, despite most participants relapsing after giving birth.
Rewarding pregnant women with up to £400 to spend on Main Street, in addition to usual support, more than doubled the proportion who were still smoke-free late in their pregnancy, and could save the National Health Service money in the long term, according to the research, published in the BMJ, led by the University of Glasgow and the University of York, England.
Although the proportion of women in the United Kingdom who smoke during pregnancy has halved over the past 20 years, those who still do are more reluctant to engage with cessation services.
Interventions using financial incentives were pioneered in the United States, but there is a lack of evidence for how effective they might be in the United Kingdom.
Vouchers linked to passing saliva tests
The phase 3 Cessation in Pregnancy Incentives Trial was based on an earlier feasibility study in Glasgow and involved 941 pregnant women aged 16 or older, with a mean age of 27.9 years when they were recruited, from seven stop-smoking services in Scotland, Northern Ireland, and England between January 2018 and April 2020. Participants self-reported that they smoked at least one cigarette a week.
The cohort was randomised into two groups: a control group who received usual stop smoking support that included the offer of counselling by trained workers combined with free nicotine-replacement therapy, and an intervention group who were given the same interventional support plus targets to receive LoveToShop vouchers.
Although vouchers to the value of £400 were on offer, earning them depended on successfully reaching four milestones. They received a first £50 voucher for engaging with stop-smoking services and setting a quit date and further vouchers for being declared smoke-free by biochemical verification at specific time points in the pregnancy.
Factors including the mother’s age, years of smoking, income, use of nicotine-replacement therapy and e-cigarettes, timing of birth, and birth weight were taken into account.
The study found that 71% of the participants in the incentive group engaged with stop-smoking services and set a quit date, compared with 64% in the control group. By late pregnancy, 126 participants (27%) of the 471 in the intervention group were smoke-free, compared with 58 (12%) of the 470 in the control group.
Most women in the trial went back to smoking
However, abstinence rates measured 6 months after giving birth were low in both groups: 6% in the intervention group vs. 4% in the control group.
The researchers also reported no significant differences in birth weight between the two groups.
Overall, the birth weight of babies from 443 intervention participants and 450 controls showed no significant difference between groups (average 3.18 kg vs. 3.13 kg).
The researchers did find a clinically important but not significant 10% increase in birth weight in the subset of participants who adhered with their treatment allocation, but they said further analysis is needed to better understand the relevance of this finding.
Severity of preterm birth was similar between groups, and all serious adverse events, such as miscarriages and stillbirths, were considered unrelated to the intervention.
The researchers acknowledged some limitations to their investigation, including that only 23% of women screened by stop-smoking services were enrolled, and that almost all participants were White. Also, the onset of COVID-19 disrupted some of the trial processes.
However, they concluded that their trial “supports implementation advocated in NICE [National Institute for Health and Care Excellence] guidelines by showing an effective, cost-effective, and generalisable pragmatic bolt-on U.K. format for incentive payments” to reduce smoking rates in pregnancy.