Mom's smoking alters fetal DNA

March 31, 2016, Cell Press
Credit: Vera Kratochvil/public domain

A study of over 6,000 mothers and their newborn children—one of the largest studies of its kind—solidifies the evidence that smoking cigarettes while pregnant chemically modifies a fetus' DNA, mirroring patterns seen in adult smokers. The researchers also identify new development-related genes affected by smoking. The work, published March 31 in the American Journal of Human Genetics, suggests a potential explanation for the link between smoking during pregnancy and health complications in children.

"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," says co-senior author Stephanie London, an epidemiologist and physician at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health. "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."

Links between smoking and chemical modifications to DNA, or methylation, have been found for developing fetuses in smaller studies, but the larger analysis gives scientists more power to uncover patterns. An international team of researchers pooled results from 6,685 newborns and their mothers around the world. Based on questionnaires, mothers were labeled as "sustained smokers" who smoked cigarettes daily throughout most of pregnancy (13 percent), "non-smokers" (62 percent), or those with "any smoking" during pregnancy (25 percent), which captured mothers who were occasional smokers or who quit smoking early on.

To analyze methylation in the newborns' DNA, researchers collected samples mainly from blood in the umbilical cord after delivery. For the newborns whose mothers fell into the "sustained smoker" category, the research teams identified 6,073 places where the DNA was chemically modified differently than in the "no smoking" newborns. About half of these locations could be tied to a specific gene.

London and her colleagues found that this collection of genes related to lung and nervous system development, smoking-related cancers, birth defects such as and palate, and more. "Many signals tied into developmental pathways," says Bonnie Joubert, an epidemiologist at the NIEHS and a co-first author on the paper. In a separate analysis, many of these DNA modifications were still apparent in older children whose had smoked during pregnancy.

Next steps include building on the preliminary gene-expression analyses conducted by the research team to better understand how these DNA modifications might influence child development and disease. For example, London says, "We already knew that is related to cleft lip and palate, but we don't know why. Methylation might be somehow involved in the process."

This is the first paper from the international Pregnancy and Childhood Epigenetics (PACE) consortium. PACE is applying the "consortium approach" to additional studies, bringing large teams of scientists together on questions such as the impact of a mother's body weight, alcohol intake, and air pollution on her child's epigenetic marks—and the effects of those marks on the child's health. "It's important to recognize the many people involved and the work that they did," says Joubert.

Explore further: Women who smoke while pregnant could alter their children's genes

More information: American Journal of Human Genetics, Joubert et al.: "DNA Methylation in Newborns and Maternal Smoking in Pregnancy: Genome-wide Consortium Meta-analysis" dx.doi.org/10.1016/j.ajhg.2016.02.019

Related Stories

Women who smoke while pregnant could alter their children's genes

July 29, 2014
The largest study of its kind has shown that smoking during pregnancy could cause epigenetic changes in the fetus, resulting in birth defects and health problems later in life. Christina Markunas of the National Institute ...

Nearly half of women who stop smoking during pregnancy go back to smoking soon after baby is born

March 15, 2016
A major new review published today by the scientific journal Addiction reveals that in studies testing the effectiveness of stop-smoking support for pregnant women, nearly half (43%) of the women who managed to stay off cigarettes ...

Unraveling the gene-environment interaction

February 17, 2016
A special issue of the journal Child Development reports on studies that take important new steps in understanding how genes and the environment interact in shaping child behavior.

Many US women still smoke before, during pregnancy: report

February 10, 2016
(HealthDay)—Despite the potential risks to their baby's health, roughly one in 10 women smoke in the three months before getting pregnant, U.S. health officials reported Wednesday.

Study finds smoking during pregnancy alters newborn stress hormones and DNA

October 17, 2014
Researchers from The Miriam Hospital have studied the effects of smoking during pregnancy and its impact on the stress response in newborn babies. Their research indicates that newborns of mothers who smoke cigarettes during ...

Blood from small children 'remembers' prenatal smoking exposure

November 23, 2015
New Johns Hopkins Bloomberg School of Public Health-led research finds that blood taken from children up to the age of five contains molecular evidence about whether their mothers smoked during pregnancy.

Recommended for you

Discovery of the 'pioneer' that opens the genome

January 23, 2018
Our genome contains all the information necessary to form a complete human being. This information, encoded in the genome's DNA, stretches over one to two metres long but still manages to squeeze into a cell about 100 times ...

Researchers identify gene responsible for mesenchymal stem cells' stem-ness'

January 22, 2018
Many doctors, researchers and patients are eager to take advantage of the promise of stem cell therapies to heal damaged tissues and replace dysfunctional cells. Hundreds of ongoing clinical trials are currently delivering ...

Genes contribute to biological motion perception and its covariation with autistic traits

January 22, 2018
Humans can readily perceive and recognize the movements of a living creature, based solely on a few point-lights tracking the motion of the major joints. Such exquisite sensitivity to biological motion (BM) signals is essential ...

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

Two new breast cancer genes emerge from Lynch syndrome gene study

January 18, 2018
Researchers at Columbia University Irving Medical Center and NewYork-Presbyterian have identified two new breast cancer genes. Having one of the genes—MSH6 and PMS2—approximately doubles a woman's risk of developing breast ...

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

TheGhostofOtto1923
3 / 5 (2) Mar 31, 2016
In the future it will be illegal to endanger a fetus by drinking, smoking, doing drugs, or not maintaining proper nutrition.

The technology will exist to monitor what a woman ingests in real-time, automatically. If poisons are detected the woman will be arrested and incarcerated in a secure medical facility.

And if there is damage to the fetus as a result of her actions she will be liable for life.

Additionally, insurance rates will be adjusted according to whether mothers agree to monitoring of her children for proper nutrition and exposure to toxins.

No woman has the right to ruin an entire life through selfishness, neglect, or addiction.

Over a few gens as this policy takes effect and healthy children become adults, crime rates and mental illness will plummet. Society will be transformed beyond recognition.
d0nkey
5 / 5 (1) Mar 31, 2016
Walmart must have a sale on tinfoil...
TheGhostofOtto1923
3 / 5 (2) Apr 01, 2016
Walmart must have a sale on tinfoil...
Donkey must be a smoker.

How's it feel to be addicted to dirt?
jlevyellow
not rated yet Apr 05, 2016
So, is Hilary right about the fetus having no rights. When does a mother become responsible for her child? Apparently, before it is born, if we are to give credence to this research!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.