MONDAY, Aug. 31, 2009 (HealthDay News) -- Women who smoke while pregnant increase their unborn child's long-term risk for health problems, including childhood asthma, cardiovascular disease and lower pulmonary function, and a new study may help experts understand why.
Researchers at the Keck School of Medicine of the University of Southern California (USC) found that maternal smoking actually changes the unborn child's DNA patterns.
The new study found that fetal exposure to maternal smoking was linked to differences in DNA methylation, an epigenetic mechanism.
Epigenetics is the study of how chemicals that attach to DNA can switch genes on and off, which leads to differences in gene expression without changing basic genetic information, according to background information in a USC news release about the study.
While epigenetics plays a role in cancer research, little is known about how epigenetic changes may be caused by environmental exposures.
In the new study, the researchers used data from the USC Children's Health Study, which examined respiratory health among children in 13 Southern California communities, as well as information from a questionnaire on maternal smoking exposure. The findings are reported in the September issue of the American Journal of Respiratory and Critical Care Medicine.
"This study provides some of the first evidence that in-utero environmental exposures such as tobacco smoke may be associated with epigenetic changes," said one of the lead authors, Carrie Breton, assistant professor in the Department of Occupational and Environmental Health at the Keck School of Medicine of USC. "This could open up a new way for researchers to investigate biological mechanisms that might explain known health effects associated with maternal smoking," she stated in the news release.
"Moms should not be smoking during pregnancy," Linda Birnbaum, director of the U.S. National Institute of Environmental Health Sciences, said in the news release. "Maternal smoking during pregnancy is not only detrimental to the health of the mom and the newborn child, but research such as this suggests that it may impact the child into adulthood and possibly even future generations as well."
The U.S. National Institutes of Health has more on smoking while pregnant.