Interventions for promoting smoking cessation during pregnancy
Abstract
Background
Smoking remains one of the few potentially preventable factors associated with low birthweight, preterm birth and perinatal death.
Objectives
To assess the effects of smoking cessation programs implemented during pregnancy on the health of the fetus, infant, mother, and family.
Search methods
We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Tobacco Addiction Group trials register (July 2003), MEDLINE (January 2002 to July 2003), EMBASE (January 2002 to July 2003), PsychLIT (January 2002 to July 2003), CINAHL (January 2002 to July 2003), and AUSTHEALTH (January 2002 to 2003). We contacted trial authors to locate additional unpublished data. We handsearched references of identified trials and recent obstetric journals.
Selection criteria
Randomised and quasi‐randomised trials of smoking cessation programs implemented during pregnancy.
Data collection and analysis
Four reviewers assessed trial quality and extracted data independently.
Main results
This review included 64 trials. Fifty‐one randomised controlled trials (20,931 women) and six cluster‐randomised trials (over 7500 women) provided data on smoking cessation and/or perinatal outcomes. Despite substantial variation in the intensity of the intervention and the extent of reminders and reinforcement through pregnancy, there was an increase in the median intensity of both 'usual care' and interventions over time.
There was a significant reduction in smoking in the intervention groups of the 48 trials included: (relative risk (RR) 0.94, 95% confidence interval (CI) 0.93 to 0.95), an absolute difference of six in 100 women continuing to smoke. The 36 trials with validated smoking cessation had a similar reduction (RR 0.94, 95% CI 0.92 to 0.95). Smoking cessation interventions reduced low birthweight (RR 0.81, 95% CI 0.70 to 0.94) and preterm birth (RR 0.84, 95% CI 0.72 to 0.98), and there was a 33 g (95% CI 11 g to 55 g) increase in mean birthweight. There were no statistically significant differences in very low birthweight, stillbirths, perinatal or neonatal mortality but these analyses had very limited power. One intervention strategy, rewards plus social support (two trials), resulted in a significantly greater smoking reduction than other strategies (RR 0.77, 95% CI 0.72 to 0.82). Five trials of smoking relapse prevention (over 800 women) showed no statistically significant reduction in relapse.
Authors' conclusions
Smoking cessation programs in pregnancy reduce the proportion of women who continue to smoke, and reduce low birthweight and preterm birth. The pooled trials have inadequate power to detect reductions in perinatal mortality or very low birthweight.
PICOs
Plain language summary
Interventions for promoting smoking cessation during pregnancy
Strategies can help support women to stop cigarette smoking in pregnancy so babies have better health.
Cigarette smoking in pregnancy is common, particularly where there is low income and social disadvantage. Smoking in pregnancy increases the risk of babies having low birthweight and being born too early. Babies often struggle to cope with life outside the womb and can suffer ill health later in life. Many mothers find it hard to stop, or to reduce, smoking during pregnancy even knowing the benefits this may have, because smoking can help them cope with stress. There are effective strategies to help and support women to stop smoking that lead to fewer premature babies and better birthweights for babies.
