Cessation in Pregnancy Incentives Trial (CPIT): a phase II trial in Scotland 2011-2013

Background: A third of ‘low birth weight’, a quarter of ‘small for gestational age’ and a sixth of ‘preterm’ births are attributable to smoking during pregnancy. Smoking in pregnancy also increases infant mortality by 40%, and may account for 150 UK infant deaths each year. In the UK one in four women smoke for part of their pregnancy and one in eight smoke throughout. Free smoking cessation services for pregnant women exist, but uptake is low in some areas and outcomes can be poor. Small trials in the USA have shown that financial incentives for smoking cessation in pregnancy can be effective, but further evidence is required. This study aimed to explore whether adding incentives to existing services is effective, acceptable and cost-effective (ISRCTN87508788). Methods: A phase II exploratory randomised controlled trial comparing standard stop smoking support for pregnant smokers with standard support plus the additional offer of shopping voucher incentives. Participants (n = 612) were pregnant smokers identified at maternity booking in Glasgow, Scotland. Vouchers up to £400 were available if clients attended counselling and set a quit date, and were abstinent from smoking at 4 and 12 weeks post quit date and in late pregnancy. The primary outcome was self-reported abstinence in late pregnancy verified by cotinine measurement. An economic evaluation and qualitative research study with pregnant women and healthcare professionals was also conducted. Results: Incentives were generally acceptable to women and healthcare professionals. The offer of £400 of shopping vouchers increased the quit rate at the end of pregnancy from 9% to 23%. ‘Gaming’ of cotinine tests was seen in 20% of control and 22% of intervention quitters. Health economic analysis indicated that incentives appear to be cost effective. Conclusion: Financial incentives may double the quit rate when added to stop smoking in pregnancy services. Standard operating procedures for this exploratory study will support a future definitive trial in the UK. If financial incentives prove to be cost effective for smoking cessation in pregnancy, their use and the methodology developed may help examine and sustain the efficacy of financial incentive payments for other health behaviour change