The effect of smoking cessation counselling in pregnant women: a meta-analysis of randomised controlled trials

Background: Pregnant smokers are often prescribed counselling as part of multicomponent cessation interventions. However, the isolated effect of counselling in this population remains unclear, and individual randomised controlled trials (RCTs) are inconclusive.

Objective: To conduct a meta-analysis of RCTs examining counselling in pregnant smokers.

Search strategy: We searched the CDC Tobacco Information and Prevention, Cochrane Library, EMBASE, Medline and PsycINFO databases for RCTs evaluating smoking cessation counselling.

Selection criteria: We included RCTs conducted in pregnant women in which the effect of counselling could be isolated and those that reported biochemically validated abstinence at 6 or 12 months after the target quit date.

Data collection and analysis: Overall estimates were derived using random effects meta-analysis models.

Main results: Our search identified eight RCTs (n = 3290 women), all of which examined abstinence at 6 months. The proportion of women that remained abstinent at the end of follow up was modest, ranging from 4 to 24% among those randomised to counselling and from 2 to 21% among control women. The absolute difference in abstinence reached a maximum of only 4%. Summary estimates are inconclusive because of wide confidence intervals, albeit with little evidence to suggest that counselling is efficacious at promoting abstinence (odds ratio 1.08, 95% confidence interval 0.84-1.40). There was no evidence to suggest that efficacy differed by counselling type.

Conclusions: Available data from RCTs examining the isolated effect of smoking cessation counselling in pregnant women are limited but sufficient to rule out large treatment effects. Future RCTs should examine pharmacological therapies in this population.