Papers

Self help smoking cessation in pregnancy: cluster randomised controlled trial

Laurence Moore, senior research fellow, ^a Rona Campbell, lecturer in health services research, ^b Amanda Whelan, research adviser, ^c Nicola Mills, research fellow, ^b Phillippa Lupton, midwife, ^d Elizabeth Misselbrook, midwife, ^e Julie Frohlich, midwife. ^f

^a Cardiff University School of Social Sciences, Cardiff CF10 3WT, ^b Department of Social Medicine, University of Bristol, Bristol BS8 2PR, ^c Centre for Research, Innovation and Graduate Studies, University of the West of England, Bristol BS16 1QD, ^d Poole Hospital NHS Trust, Poole BH15 2JB, ^e United Bristol Healthcare Trust, St Michael's Hospital, Bristol BS2 8EG, ^f North Bristol NHS Trust, Southmead Hospital, Bristol BS10 5NB

Correspondence to: L Moore
MooreL1{at}cf.ac.uk

Objectives: To evaluate the effectiveness of a self help approach to smoking cessation in pregnancy.
Design: Pragmatic cluster randomised controlled trial with community midwife as the unit of randomisation.
Setting: Three NHS hospital trusts in England.
Participants: 1527 women who smoked at the start of pregnancy.
Intervention: A series of five self help booklets comprising a step by step programme to increase motivation for quitting smoking and to teach strategies for cessation and relapse prevention. The first booklet was given to the women by a midwife at the earliest opportunity in antenatal care, together with a booklet for partners, family members, and friends. The remaining four booklets were mailed directly to the women.
Main outcome measures: The primary outcome was smoking cessation validated by cotinine measurement at the end of the second trimester of pregnancy. Other outcomes were self reported smoking status and cigarette consumption among daily smokers. Qualitative data exploring the acceptability of the intervention and the way that smoking cessation advice was delivered in both trial arms were also collected.
Results: Smoking cessation rates were low: the cotinine validated rates were 18.8% (113/600) in the intervention group and 20.7% (144/695) in the normal care group (difference 1.9%, 95% confidence intervals 3.5% to 7.3%). Self reported quit rates were higher. In the intervention group, 156 (25.6%) women reported not smoking for at least seven days, compared with 207 (29.1%) in the normal care group. In both groups, median self reported daily cigarette consumption among daily smokers was 10 cigarettes per day. Pregnant women and midwives approved of the intervention, but the way in which it was delivered varied considerably. For the primary smoking outcome, the degree of clustering at the midwife level was non-trivial (intracluster correlation coefficient 0.031).
Conclusion: The self help intervention was acceptable but ineffective when implemented during routine antenatal care. More intensive and complex interventions, appropriately targeted and tailored, need to be developed and evaluated. Validated smoking cessation rates among pregnant women are substantially lower than the self reported rates on which current smoking policy is based.

What is already known on this topic The most recent systematic review evidence suggests that self help interventions designed specifically for pregnant smokers can be effective in increasing cessation rates These reviews, however, are based mainly on efficacy trials involving staff who are specifically employed to provide the intervention In other attempts to assess the effectiveness of such an approach within routine antenatal care, it has been difficult to implement scientifically rigorous evaluations What this study adds A low cost, self help intervention was ineffective when implemented during routine antenatal care, even though it was acceptable to midwives and pregnant women Validated smoking cessation rates among pregnant women are substantially lower than the self reported rates on which current smoking policy is based