Women who smoke during pregnancy may be increasing their child's risk of becoming obese, according to researchers at the University of Munich.

Data from a school entry health examination in six public health offices in Germany's Bavaria region in 1999 to 2000 were used to assess the relation between maternal smoking during pregnancy and childhood obesity.

A total of 6,483 children, ages 5 to 7, were included in the study. A body mass index greater than the 90th percentile was defined as overweight and a body mass index greater than the 97th percentile was defined as obese.

Children whose mother smoked during pregnancy were twice as likely to be obese -- and 43 percent more likely to be overweight -- as children whose mother did not smoke, according to the study published in the American Journal of Epidemiology.

A child's risk of being overweight or obese increased with the number of cigarettes the mother smoked during the pregnancy.

Other sources: American Journal of Epidemiology