Smoking during pregnancy has long been suspected to contribute to several birth defects in neonates. However, the exact biological effects of smoking has not been scientifically documented thus far.
In a new study, scientists have uncovered that smoking induces methylation patterns in DNA that could possibly link to several birth defects.
Researchers in the National Institute of Environmental and Health Sciences in Research Triangle Park, North Carolina conducted a population-based study to analyze the DNA methylation patterns of children born to mothers who smoked during pregnancy.
Studies were conducted on 6685 mothers and their newborns around the world. Of these about 13% of the women were daily smokers and another 25% admitted to occasional smoking during pregnancy.
Umblical cord blood samples were collected after delivery and analyzed for the DNA methylations patterns. They observed 6073 places where the babies DNA was methylated differently from the DNA of the babies of non-smoking mothers.
Of these, many were found on or near the collection of genes that were related to cranio-facial defects, birth defects, smoking-related cancers and lung and nervous system development.
“We already knew that smoking during pregnancy, or after the child is born, is to be avoided at all costs,” said senior study author Dr. Stephanie London, deputy chief of the epidemiology branch at the National Institute of Environmental and Health Sciences.
Also adding to the study, the researchers analysed DNA methylation of a smaller group of older children and found that some of the methylation patterns persisted in children born to mothers who smoke during pregnancy.
“It’s possible that smoking during pregnancy might hijack systems in babies that determine how DNA is deployed and alter programs in the cells in a way that impacts future health”, said Andrea Baccarelli, an environmental epigenetics researcher at Harvard University in Boston, who wasn’t involved in the study.
From their data, the authors of the study conclude that the findings suggest that difference in DNA methylation patterns might contribute to certain birth defects or medical problems in babies born to mothers who are both occasional and regular smokers.
They have published their findings in The Americal Journal of Human Genetics.