Smoking doesn't just have an impact on the person who's doing it. It could also impact those around them. Now, scientists have found that mothers who smoke may actually be altering the DNA of their fetuses.
Previous, smaller studies have found that there are links between smoking and the chemical modifications of DNA in fetuses. However, this latest study is a much larger analysis, and it may allow scientists to uncover patterns that haven't been seen before.
Researchers pooled the results from 6,685 newborns and their mothers around the world. The mothers themselves were categorized into three groups. One group included mothers who smoked cigarettes daily during their pregnancy. The second group included mothers who didn't smoke, and the third group included mothers who occasionally smoked and who quit smoking early on in their pregnancy.
The scientists collected samples of the newborns' DNA from blood in the umbilical cord after delivery. Surprisingly, the newborns with mothers who smoked daily had modified DNA. In fact, the scientists identified 6,073 places where the DNA was chemically modified differently than in the newborns who had mothers who didn't smoke. About half of these locations could be tied to one specific gene.
While a lot of the locations were tied to one specific gene, there were also impacts on other genes. These were genes related to lung and nervous system development, smoking-related cancers, birth defects such as cleft lip and palate, and more.
"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," said Stephanie London, co-author of the new study and epidemiologist and physician at the 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."
The findings show that smoking during pregnancy can actually impact the fetus in many ways. This is particularly important when giving mothers advice during their pregnancy.
The scientists hope to conduct further research to understand how the DNA modifications might influence child development and diseases.
The findings were published in the March 31 issue of the journal American Journal of Human Genetics.