In Belgium, public smoking bans were introduced progressively since 2006. As of 2010, smoking is illegal in most public buildings, restaurants, and bars serving food. Researchers at Hasselt University have since noted a 3.1 percent decline in perterm births in 2007 and a further drop of 2.7 percent in 2010. Smoking is known to cause premature births and impaired development, but this is one of the few studies that looks at the effects of a smoking ban. While improvements in healthcare may lend to these results , it is understood that a decrease in smoking is the main reason.
Seppa, Nathan. "Smoking Ban Cuts Preterm Births." Science News. 23 March 2013: 18. Print.