Smoking, nicotine and pregnancy 2 (SNAP2) trial: protocol for a randomised controlled trial of an intervention to improve adherence to nicotine replacement therapy during pregnancy
Sarah Lewis,
Catherine Hewitt,
David Torgerson,
Felix Naughton,
Paul Aveyard,
James Brimicombe,
Stephen Sutton,
Linda Bauld,
Ivan Berlin,
Tim Coleman,
Lisa Mcdaid,
Sue Cooper,
Michael Ussher,
Kavita Vedhara,
Anne Dickinson,
Steve Parrott,
Katharine Bowker,
Charlie Welch,
Lucy Phillips,
Ross Thomson,
Miranda M Clark,
Joanne Emery,
Gill Parkinson,
Andrew McEwen
Affiliations
Sarah Lewis
9 School of Medicine, University of Nottingham, Nottingham, UK
Catherine Hewitt
Department of Health Sciences, University of York, York, UK
David Torgerson
professor
Felix Naughton
2 Addiction Research Group, School of Health Sciences, University of East Anglia, Norwich, UK
Paul Aveyard
6 Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
James Brimicombe
12 Cambridge Research Methods Hub, University of Cambridge, Cambridge, UK
Stephen Sutton
11 Behavioural Science Group, University of Cambridge, Cambridge, UK
Linda Bauld
director
Ivan Berlin
8 Department of Medical Pharmacology, Pitié Salpêtrière Hospital-Sorbonne Université, Paris, France
Tim Coleman
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Lisa Mcdaid
2 Addiction Research Group, School of Health Sciences, University of East Anglia, Norwich, UK
Sue Cooper
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Michael Ussher
3 Population Health Research Institute, St George`s University of London, London, UK
Kavita Vedhara
15 School of Psychology, Cardiff University, Cardiff, UK
Anne Dickinson
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Steve Parrott
10 Department of Health Sciences, University of York, York, UK
Katharine Bowker
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Charlie Welch
7 York Trials Unit, Department of Health Sciences, University of York, York, UK
Lucy Phillips
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Ross Thomson
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Miranda M Clark
1 Centre for Academic Primary Care, School of Medicine, University of Nottingham, Nottingham, UK
Joanne Emery
2 Addiction Research Group, School of Health Sciences, University of East Anglia, Norwich, UK
Gill Parkinson
7 York Trials Unit, Department of Health Sciences, University of York, York, UK
Andrew McEwen
13 National Centre for Smoking Cessation and Training (NCSCT), Dorchester, UK
Introduction Smoking during pregnancy is harmful to unborn babies, infants and women. Nicotine replacement therapy (NRT) is offered as the usual stop-smoking support in the UK. However, this is often used in insufficient doses, intermittently or for too short a time to be effective. This randomised controlled trial (RCT) explores whether a bespoke intervention, delivered in pregnancy, improves adherence to NRT and is effective and cost-effective for promoting smoking cessation.Methods and analysis A two-arm parallel-group RCT was conducted for pregnant women aged ≥16 years and who smoke ≥1 daily cigarette (pre-pregnancy smoked ≥5) and who agree to use NRT in an attempt to quit. Recruitment is from antenatal care settings and via social media adverts. Participants are randomised using blocked randomisation with varying block sizes, stratified by gestational age (<14 or ≥14 weeks) to receive: (1) usual care (UC) for stop smoking support or (2) UC plus an intervention to increase adherence to NRT, called ‘Baby, Me and NRT’ (BMN), comprising adherence counselling, automated tailored text messages, a leaflet and website. The primary outcome is biochemically validated smoking abstinence at or around childbirth, measured from 36 weeks gestation. Secondary outcomes include NRT adherence, other smoking measures and birth outcomes. Questionnaires collect follow-up data augmented by medical record information. We anticipate quit rates of 10% and 16% in the control and intervention groups, respectively (risk ratio=1.6). By recruiting 1320 participants, the trial should have 90% power (alpha=5%) to detect this intervention effect. An economic analysis will use the Economics of Smoking in Pregnancy model to determine cost-effectiveness.Ethics and dissemination Ethics approval was granted by Bloomsbury National Health Service’s Research Ethics Committee (21/LO/0123). Written informed consent will be obtained from all participants. Findings will be disseminated to the public, funders, relevant practice/policy representatives, researchers and participants.Trial registration number ISRCTN16830506.Protocol version 5.0, 10 Oct 2023.
