Experts have long recognized that smoking during pregnancy raises serious risks for babies, including miscarriage, preterm birth, and developmental delays. Now, a major international study published in the American Journal of Human Genetics reveals it also triggers chemical changes to fetal DNA, linking maternal smoking to lifelong health issues in children.
Researchers identified key genes tied to child development that tobacco exposure disrupts—changes strikingly similar to those in adult smokers. Critically, since the fetus avoids direct smoke inhalation, these modifications occur through the placenta.
This comprehensive study examined over 6,600 mothers and their children worldwide, differentiating “persistent” smokers (daily during pregnancy) from “occasional” ones. Non-smokers made up 62% of participants, occasional smokers 25%, and persistent smokers 13%.
By analyzing umbilical cord blood samples at birth, scientists detected 6,073 modified DNA sites in babies of persistent smokers. Strikingly, about half of smoking-related DNA alterations impact genes vital for lung and nervous system development, as well as those associated with cancer risk. The research also points to heightened chances of congenital anomalies like cleft lip.
Importantly, the study does not evaluate electronic cigarette effects on the fetus.
