Mothers who smoke when they’re pregnant may cause genetic damage in their babies, findings from a new study suggest. In fact, one common type of chromosome damage linked to maternal smoking is known to increase the risk of blood cancers.

While smoking is known to have a number of adverse effects on pregnancy, there has been limited information about on any possible genetic damage to the fetus, according to the report in Wednesday’s Journal of the American Medical Association.

To investigate, Dr. Josep Egozcue, from Universitat Autonoma de Barcelona and colleagues analyzed fetal cells obtained during routine amniocentesis from 25 women who smoked and 25 controls. The women in the smoking group smoked at least 10 cigarettes per day.

The rate of structural chromosomal abnormalities in the smoking group was 12.1 percent, much higher than the rate seen in controls - 3.5 percent - the researchers report.

Analysis of the 689 breakpoints identified revealed that one at a specific location of chromosome 11, which is often tied to blood cancers like leukemia, was most commonly affected by smoking.

In a related editorial, Dr. David M. DeMarini and Dr. R. Julian Preston, from the US Environmental Protection Agency in Research Triangle Park, North Carolina, comment that the current study represents “the first report of tobacco-smoke-associated genotoxic damage in fetal epithelial cells from mothers who smoke.”

Still, the study does have certain limitations, such as no direct or indirect measure of smoke exposure, and, therefore, the findings should be regarded as preliminary, they add.

SOURCE: Journal of the American Medical Association, March 9, 2005.