Smoking bans reduce preterm births, but not low birthweight

According to a recent study in The Lancet, a reduction in preterm births and childhood hospital visits for asthma are additional benefits to public smoking bans.

Researchers from Maastricht University Medical Centre, Brigham and Women’s Hospital, and the University of Edinburgh searched 14 online databases from January, 1975 to May, 2013 for studies reporting associations between smoking bans and 1 or more early-life health indicator and identified 11 eligible studies published 2008 to 2013. Included were studies undertaken with designs approved by the Cochrane Effective Practice and Organisation of Care that reported associations between smoking bans in workplaces, public places, or both, and one or more predefined early-life health indicators.

Primary outcomes included preterm birth, low birthweight, and hospital visits for asthma. The studies covered more than 2.5 million births and 247,168 asthma exacerbations. The 5 North American studies looked at local bans, while the 6 European studies covered national bans. Risk of bias was high for 1 study, moderate for 6, and low for the remaining 4.

The investigators found that smoking bans led to a significant reduction in preterm births (4 studies, 1,366,862 individuals; -10.4% [95% confidence interval {CI} -18.8 to -2.0]; P=0.016)and hospital visits for asthma (3 studies, 225,753 events; -10.1% [95% CI -15.2 to -5.0]; P=0.0001). However, no significant effect on low birthweight was associated with smoking bans (6 studies, >1.9 million individuals; 1.7% [95% CI -5.1 to 1.6]; P=0.31).

The study authors concluded that smoking bans have the potential to significantly curb preterm deliveries and childhood asthma attacks. Their study, they said, provides strong support for the World Health Organization’s recommendation for nationwide smoking bans.

To get weekly advice for today's Ob/Gyn, subscribe to the Contemporary Ob/Gyn Special Delivery.