Housing evidence / case study · working draft
Glasgow: pregnancy incentive trial (CPIT II)
A randomised pregnancy trial in a materially deprived population tested vouchers in addition to specialist cessation care.
01 / THE APPROACH
What was tried
This Glasgow trial tested whether shopping vouchers could help pregnant women engage with specialist cessation care and stop smoking. It recruited 612 women and randomly allocated them to usual support or the same support with incentives worth up to £400.
Rewards were staged: £50 for attending and setting a quit date, £50 for a verified four-week quit, £100 at twelve weeks and £200 for verified quitting in late pregnancy. The treatment offer continued alongside the rewards. Breath tests and biological samples checked smoking status rather than relying only on what women reported.
02 / THE FINDINGS
What was learned
In late pregnancy, 69 women offered incentives (22.5%) were verified as having stopped smoking, compared with 26 (8.6%) in the usual-care group.
The trial showed that adding incentives could improve the late-pregnancy outcome in this setting. It did not establish that women remained smoke free after birth or that the same reward schedule would have the same effect among other groups.
03 / TRANSFER TO WALES
What Wales could learn
The service combined specialist pregnancy care with staged vouchers and checks at defined milestones. Treatment continued alongside the incentive offer.
The trial demonstrates an added benefit during pregnancy. Delivering that model involved appointments, sample checks and reward administration; the late-pregnancy result does not show sustained quitting after birth.
Sources & review
Public BMJ trial and open university-repository copy. Primary trial checked. This is the earlier CPIT II study, separate from the later multicentre CPIT III trial.
