Women Who Smoke During Pregnancy Alter Baby’s DNA

By Casey Heely April 1, 2016

Although doctors already strongly advise women not to smoke while they are pregnant, new evidence offers further evidence for the harm it does. A study in the American Journal of Human Genetics, released this week, suggests that smoking during pregnancy may cause alterations to the baby’s DNA.

Smoking during pregnancy affects what’s known as “methylation,” the study found. The process of methylation determines how DNA works, and if certain genes are not methylated, or are methylated differently than they should be, it can result in a greater likelihood of the baby acquiring certain diseases.

“When women smoked daily during pregnancy, researchers identified 6,073 places where their babies’ DNA was methylated differently from the DNA of nonsmokers’ infants,” according to Yahoo news.

The areas of DNA that the researchers found were most affected included those that determine the development of the lungs and nervous system, cancers related to smoking, and birth defects such as cleft lip and palate.

Despite previous studies about the harmful effects of smoking while pregnant, the study found that “many pregnant women still smoke, including 12.3% in the U.S.”

This study gives more insight into the particular mechanisms that cause these harmful effects on the babies of mothers who smoke and links them to the effect smoking may have on a baby’s DNA. Although it doesn’t prove this link, it suggests how these differences in DNA methylation may be involved in the birth defects or medical problems of babies whose mothers smoked during pregnancy.

The study also found some evidence that not only infants but also older children had some of these DNA differences, which persisted if their mother smoked during pregnancy.

“Even if the reasons for these cellular changes aren’t certain, the message for patients is clear,” Paul Fowler, a director of the Institute of Medical Sciences at the University of Aberdeen in the U.K told Yahoo news. He added, “What this new study does is so strongly reinforce the message that there can be long-term consequences for their babies after birth,” according to Yahoo.