Trial name or title	Cessation in Pregnancy Incentives Trial (CPIT).
Methods	Individually randomised controlled trial.
Participants	600 pregnant smokers identified at maternity booking who, when contacted by specialist cessation services, agree to having their details passed to the NHS Smokefree Pregnancy Study Helpline to discuss the trial
Interventions	Standard care plus the additional offer of financial voucher incentives to engage with specialist cessation services and/or to quit smoking during pregnancy £50 for attending a face-to-face appointment with their NSPS adviser and setting a quit date; £50 if quit 4 weeks after their quit date corroborated by a carbon monoxide breath test result less than 10 ppm collected by a research nurse; £100 if quit after 12 weeks corroborated by a carbon monoxide breath test collected by a research nurse; £200 if they self-report quit for at least 2 months when contacted for primary outcome assessment by the Helpline at 34 to 38 weeks’ gestation
Outcomes	Self-reported smoking in late pregnancy verified by cotinine measurement
Starting date	Recruitment started in December 2011. On 9 June 2012, 199 of 600 were enrolled in the 12 month trial
Contact information	David Tappin: david.tappin@glasgow.ac.uk Paediatric Epidemiology and Community Health Unit, Section of Child Health, Division of Developmental Medicine, Glasgow University, Yorkhill Campus, Glasgow G3 8SJ, Scotland, U.K
Notes	Current Controlled Trials ISRCTN87508788