A pragmatic randomized controlled trial of physical activity as an aid to smoking cessation during pregnancy

Smoking during pregnancy is the most important cause of preventable harm to infants. Stopping smoking reduces this harm and also reduces women's risks of developing other harmful effects of smoking. Smoking cessation counselling can help pregnant smokers to stop but success rates are low, few women attend such treatments and many pregnant women prefer not to use pharmaceutical aids to cessation. Moderate intensity activity (e.g. brisk walking) is recommended as part of antenatal care and there is some evidence that supervised exercise (e.g. treadmill walking) can help non-pregnant women to stop smoking. Pilot work has shown that many pregnant women would be happy to join a research study testing exercise for smoking cessation. The study will assess whether supervised exercise, added to standard smoking cessation support, can help pregnant smokers to quit. 866 pregnant smokers will attend six weekly sessions of smoking cessation counselling and half of them will be randomized to also receive 14 individual exercise sessions over eight weeks. The trial will primarily assess whether the exercise intervention increases the womens' rates of biochemically validated smoking cessation up to the end of pregnancy. The women will also be asked about their smoking six months after the birth. In addition, differences between the groups will be examined for the womens' physical activity levels, withdrawal symptoms, urges to smoke, depression, weight, perinatal outcomes (e.g. birth weight) and self-confidence to stop smoking. If the intervention was found to be effective it would provide a valuable blueprint for the construction of physical activity programmes for pregnant smokers, and for smokers in general, receiving smoking cessation treatment through the NHS.