A recent study that evaluated the impact of the introduction of smoke-free legislation on preterm births identified yet another benefit of smoking bans. The findings, which were published in BMJ, confirm that smoking bans significantly reduce the risk of preterm delivery.

The health risks associated with smoking during pregnancy are already very well known – it can cause the unborn child to not develop properly, as well as shortening gestation. Yet little was known about the extent banning smoking might have on birth outcomes

The researchers analyzed whether the recent Belgian smoking bans had any effect on pre-term births. Smoke-free legislation was introduced in Belgium in three different phases; firstly, they banned smoking in public places and workplaces, they then banned smoking in restaurants, and finally banned it in bars that also serve food.

The authors noted:

“In Belgium, smoke-free legislation was implemented in different phases. These successive steps in legislation gave us the opportunity to investigate possible stepwise changes in preterm delivery.”

A total of 606,877 live babies who were born between 24-44 weeks of gestation were analyzed by the investigators. They noticed that following the smoking bans, the prevalence of preterm births (birth before 37 weeks) significantly decreased – a trend that did not exist prior to the bans.

As of January 1, 2007, when smoking was banned in restaurants, there was a 3.13% reduction in the risk of pre-term births. This went down by a further 2.65% following the ban on smoking in bars serving food after January 2010. The reduction in pre-term births considered all other potential factors, such as mother’s age and socioeconomic status as well as changes in air pollution.

The study has very important public health implications, considering that even a small drop in gestational age is associated with a series of health complications in early and later life.

The authors conclude:

“Our study shows a consistent pattern of reduction in the risk of preterm delivery with successive population interventions to restrict smoking. It supports the notion that smoking bans have public health benefits even from early life. More and more countries in Europe are adopting stricter legislation on smoking in public places. These results underscore the public health benefit of smoking ban policies.”

A previous study, published in PLoS Medicine, identified similar results in the reduction of pre-term deliveries since Scotland introduced comprehensive smoke-free legislation.

Written by Joseph Nordqvist