Women know what to avoid in pregnancy. Alcohol is off limits, many medications -- such as Accutane -- can cause permanent fetal damage and cocaine is certainly not recommended.
But suppose your obstetrician said: "I want you to make sure you don't get stressed out. Your stress could permanently alter your child's brain and lead her to respond inappropriately to stressful situations forever."
This isn't going to happen tomorrow, but new research is demonstrating that it's not just in utero exposure to toxic compounds that influence fetal development. What you eat, how much you weigh and maybe what you feel all influence the way a fetus' genetic code program her development and her response to her environment.
A recent article by German psychologists Thomas Elbert, Maggie Schauer and their colleagues at the University of Konstanz showed the children of women who were under extreme stress during their pregnancy had an abnormal "methylation" pattern on the DNA coding for a stress steroid receptor.
The researchers studied a group of children, ages 10-19, and their mothers. They asked the mothers if they had been the victims of partner violence during or around the time of their pregnancy. Then they studied the DNA methylation in the children of a particular region of the genetic code that specifies the glucocorticoid receptor, a regulator in the stress axis.
More than a decade after their birth, the children of women exposed to partner violence during their pregnancy had more DNA methylation of this receptor than children whose mothers had not been exposed to partner violence. Interestingly, children born to women exposed to partner violence before or after their pregnancy (but not during their pregnancy) did not have increased methylation.
The link between behavior and long-term genetic outcome of offspring is not new. Adults who were in utero during the Dutch Famine of 1944 were noted to have a remarkably high rate of coronary artery disease, diabetes, obesity, and other health problems. This surprising phenomenon was explained by British epidemiologist David Barker, whose theory has become known as the "Barker Hypothesis."
Barker's theory, since proven in animal and human experiments, was that fetuses adapted to nutritional deprivation during pregnancy by modifying their genome in a process termed epigenetic modification, to survive on less. This made sense: If the fetus could exist on fewer calories, it would be more likely to survive. Metabolism slowed down, growth was diminished and unnecessary activity was reduced.
However, once born and provided with normal nutrition, these adaptations, hard-coded in these "epigenetic modifications," became maladaptive. Slow metabolism lead to obesity, altered breakdown of fat lead to coronary artery disease and abnormal insulin function lead to diabetes.
Other related research has shown that obesity and a high-fat diet during pregnancy predisposes children to diabetes and obesity.
Taken together, these different studies have led to the recognition that what you eat during pregnancy may have a lasting impact on the long-term health of your child.
My suspicion is that these findings are not surprising: women are used to modifying their diet and their intake of drugs and alcohol during pregnancy for the sake of their fetus. But their stress? Their emotional state? Are we ready to "blame" mothers for their psychological health during pregnancy if their child ends up a basket case?
Connecting these dots may be a bit of a leap -- there's a world of difference between the stress of a job and the unpredictable horror of an abusive relationship -- but as the links between diet and behavior and the long-term health of offspring are explored and unwound, we may come to see our contribution to our children's health in a different light.
I asked Tufts University School of Medicine psychiatrist Vivian Halfin to help me interpret this conundrum, and she was able to help talk me down off the edge. She pointed out, correctly, that the German study was extremely small -- it certainly contained too few subjects to warrant major sociological conclusions.
"Domestic violence is something that everyone agrees is a stressor," she said, "But are people going to get unglued if they get stressed about the minor stuff as well? I would hope that if people feel stressed, they would seek out an evaluation because they may have depression or anxiety, both treatable conditions, which they may label as stress and incorrectly assume to be something they have to live with."
I feel better already.
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