Collaboration with Cambridge University Hospitals NHS, St George's, University of London, University of East Anglia, University of Edinburgh and University of Leicester.
We are acting as the Scottish recruitment hub for a large randomised controlled trial. Compared the effectiveness of an intervention for preventing postpartum return to smoking with usual care 
Health Condition(s) or Problem(s) Studied 
Healthy postpartum women who have achieved abstinence from tobacco smoking prior to or during pregnancy. The intervention is to prevent postpartum relapse to tobacco smoking.  
Intervention(s) 
BabyBreathe intervention: This is a complex behavioural intervention involving health visitor support and advice at every routine antenatal and postnatal contact, motivational products (BabyBreathe leaflets and BabyBreathe box), nicotine replacement therapy, electronic carbon monoxide testing, text message support and self-help via the BabyBreathe app and website, offering tailored advice and support for 12 months postpartum. 
Control: Usual antenatal and postnatal care as per the NHS maternity care pathway (no routine relapse prevention support). 
Key Inclusion and Exclusion Criteria 
Study population:  
Pregnant women who have quit smoking in the 12 months before or during pregnancy, where smoking abstinence is defined as having stopped smoking for at least 4 weeks prior to recruitment.  
Inclusion criteria: 
Pregnant women who have stopped smoking completely in the 12 months prior to pregnancy, or at any time during pregnancy. 
At 26 weeks gestation or any time up until birth, woman confirms having not smoked a single puff of a cigarette for at least 4 weeks. 
Able to read and understand English. 
Willing and able to give informed consent for participation in the study. 
Expired carbon monoxide (CO) reading less than 4 parts per million (ppm). 
Exclusion criteria: 
Under the age of 16 
Study Type 
Randomised controlled trial.  
Target Sample Size 
880 
Primary Outcome(s) 
The primary effectiveness outcome is self-reported continuous postpartum smoking abstinence, biochemically validated by CO monitoring at 12 months postpartum, with cut off of less than 8ppm (a reading of 7ppm or less), according to the Russell standard.  Adapting the Russell standard, we will grant a period of ‘grace’, allowing up to 5 smoking lapses between the birth of the baby and the 12-month follow-up, before the outcome is counted as relapse.   
Key Secondary Outcomes 
At 6 months postpartum: 
Postpartum self-reported abstinence 
Self-reported time to relapse 
Self-reported partner smoking status 
Relapse predictors 
Self-efficacy related to long-term smoking abstinence 
Edinburgh postnatal depression scale 
Behavioural support use 
Nicotine product use 
Perceived stress 
AUDIT-C 
EQ-5D-5L 
At 12 months postpartum: 
Self-reported time to relapse 
Self-reported partner smoking status 
Relapse predictors 
Self-efficacy related to long-term smoking abstinence 
Edinburgh postnatal depression scale 
Behavioural support use 
Nicotine product use 
Perceived stress 
AUDIT-C 
EQ-5D-5L 
Participant resource use 
Infant health outcomes