Mental Health
Mom's prenatal stress raises risk of asthma, allergy in babies
By Sue Mueller
May 19, 2008 - 1:24:01 PM

MONDAY May 19, 2008 (foodconsumer.org) -- A new study has found more of allergy antibodies in babies whose moms experienced stress during pregnancy, suggesting that women's prenatal stress may predispose their children to asthma and allergy later in their life.  

Researchers from Harvard Medical School presented the study at the American Thoracic Society's 2008 International Conference in Toronto on Sunday May 18.

Certain environmental substances that cause allergies can increase a child's chance of developing asthma and the effects may begin prior to birth, said Rosalind J. Wright, M.D., M.P.H., assistant professor of medicine at Brigham & Women's Hospital and Harvard Medical School.

But mother's stress during pregnancy can also influence the babies developing immune system, according to a press release by American Thoracic Society.

Animal studies showed the combination of stress and allergen exposure during pregnancy may boost the effects on the immune system, making the animals more susceptible to asthma and allergy.

For the study, the researchers followed 387 pairs of mothers and infants to examine levels of maternal stress and mother's exposure to dust mite allergen in their homes and measure cord blood immunoglobulin E (IgE).  These infants were enrolled in the Asthma Coalition on Community, Environment, and Social Stress (ACCESS) project in Boston.

IgE antibodies are a major type of immunoglobulin made by the body, which are implicated in allergic reactions.  When encountering an allergen, they signal mast cells to release histamine or other chemicals into the surrounding tissue, which trigger the common allergic reactions.

The researchers found increased levels of IgE in cord blood in infants whose mothers experienced higher levels of stress during pregnancy. The association held true even when they were exposed to relatively low levels of dust mite and other factors such as race, class, education and smoking habit were considered.

"This research adds to a growing body of evidence that links maternal stress such as that precipitated by financial problems or relationship issues, to changes in children’s developing immune systems, even during pregnancy," said Dr. Wright.

"This further supports the notion that stress can be thought of as a social pollutant that, when 'breathed' into the body, may influence the body's immune response similar to the effects of physical pollutants like allergens, thus adding to their effects."

IgE is just a marker, meaning it is still uncertain whether infants with high levels of IgE would definitely develop asthma or allergic reactions.  Dr.  Wright noted that this needs to be confirmed by continued follow-up.  Also the findings need to be replicated in a larger study population to give a clearer picture of the association between prenatal stress and childhood asthma development.

"It is notable that these findings were obtained in a U.S. urban population, which may be more likely to be simultaneously exposed to multiple factors, including stress and indoor allergens. More studies like this may help explain why asthma occurs more frequently in these high-risk groups," said Junenette Peters, Sc.D., postdoctoral research fellow who presented these results.

Regardless, the results suggest that when such exposures - prenatal stress, allergen exposure - occur together, there is an elevated increase in risk of asthma and allergies.

An early study led by Entringer S and colleagues from the University of Trier in Germany and published in the April 2008 issue of Am. J. Obstet. Gynecol. showed that prenatal psychosocial stress exposure was associated with insulin resistance in young adults.  

The current study is the first to show a relationship between stress exposure during pregnancy and potentially increased risk of asthma and allergies, according to the release by American Thoracic Society.