THURSDAY, March 31, 2016 (HealthDay News) -- When a pregnant woman smokes, the fetus' DNA is altered in ways also seen in adult smokers, researchers say.
The researchers were also able to pinpoint new development-related genes that were affected by a mother-to-be's smoking.
The findings may help improve understanding about the connection between smoking during pregnancy and children's health problems, the study authors said.
For the study, researchers collected blood samples from newborns, mainly from the umbilical cord. Compared to babies of nonsmokers, those born to regular smokers had over 6,000 spots where DNA was chemically modified.
About half of those locations could be linked to specific genes, including those involved in lung and nervous system development, birth defects such as cleft lip and palate, and smoking-related cancers.
The investigators also found that many of these DNA changes were still present in older children whose mothers had smoked during pregnancy.
The study was published March 31 in the American Journal of Human Genetics.
Smaller studies have found links between smoking during pregnancy and chemical changes in fetal DNA, the authors of the new study noted. But this large study, which included over 6,000 mothers and their children, improved the researchers' ability to detect patterns.
"I find it kind of amazing when we see these epigenetic signals in newborns, from in utero exposure, lighting up the same genes as an adult's own cigarette smoking. There's a lot of overlap," study co-senior author Stephanie London said in a journal news release. She is an epidemiologist and physician at the U.S. National Institute of Environmental Health Sciences.
"This is a blood-borne exposure to smoking -- the fetus isn't breathing it, but many of the same things are going to be passing through the placenta," London explained.
The March of Dimes has more about smoking during pregnancy.