Do smoking bans reduce preterm births?
Bans on public smoking may benefit the very youngest members of society, with research showing that fewer babies are born prematurely after smoking bans are put in place.
BMJ Group News
What do we know already?
In the last 10 years, smoking in public places has been banned in many countries, including the UK. The goal of these bans is to improve public health, as second-hand smoke has been linked to several health problems, including asthma flare-ups and heart disease. Research also suggests that pregnant women exposed to second-hand smoke are more likely to have their babies early (preterm), which can lead to health problems in infancy and later in life.
In the study, researchers wanted to find out whether public smoking bans helped to reduce these early births. They focused on the Flanders region of Belgium, where bans on public smoking were introduced in three stages: smoking was banned in public places and most workplaces in January 2006; in restaurants in January 2007; and in bars serving food in January 2010. The researchers compared how many babies were born preterm before and after the start of each of the smoking bans. Preterm births were defined as those occurring before the 37th week of pregnancy.
In total, the researchers looked at more than 606,800 babies delivered at 24 to 44 weeks of pregnancy. They looked only at ‘singleton’ babies, as twins and other multiple births are more likely to have an early delivery.
What does the new study say?
There was a decline in preterm births after each of the bans in public smoking was put in place.
For example, after the 2007 ban on smoking in restaurants, preterm births dropped by more than three percent. Overall, the researchers estimated that there were six fewer preterm births for every 1,000 babies born in the five years after 2007, taking into account all the smoking bans. They found no signs that preterm births were already declining before the smoking bans were put in place.
How reliable is the research?
This is a good-quality study that looked at a large number of births. The researchers also explored whether other factors might have affected the number of preterm births - such as the mothers’ ages and changes in air pollution - but they found no link. This strengthens their findings.
However, they weren’t able to account for all factors that might have had an effect, including whether the mothers smoked. It’s possible that a decline in smoking among pregnant women might also have led to fewer preterm births.
So, although the researchers found a strong link between smoking bans and a decline in preterm births, we can’t yet be certain that the link is genuine.
What does this mean for me?
We need more studies to confirm these findings and understand the impact of smoking bans on preterm births and other health issues. However, we do know that smoking can affect an unborn baby’s growth and development, and second-hand smoke may have similar effects. If you are pregnant, it’s best to avoid smoke whenever possible.