Stressed Moms May Have Sneezy Kids
Effect on pregnant women's immune system might be passed on

(HealthDay News) -- The stress a mother experiences just might increase her children's risk of developing asthma and allergies.

That's the conclusion of a study that found that babies who were born to mothers who had high levels of stress had more IgE -- an antibody involved in allergies and asthma -- in their blood at birth than did babies born to calmer moms.

"Moms who had elevated levels of stress had children who seemed to be more reactive to allergens, even when exposed to low levels of allergens," Dr. Rosalind Wright, an assistant professor of medicine at Brigham and Women's Hospital and Harvard Medical School in Boston and a co-author of the study, told HealthDay .

The researchers theorized that stress might make women more susceptible to allergens, because it "may make the cells more permeable" so that even low levels of exposure trigger a reaction, another author of the study, Junenette Peters, told HealthDay . And, she said, women whose immune systems are altered by stress might, in turn, pass down that trait to their infants.

Peters, a postdoctoral research fellow at Harvard Medical School , presented the findings at an international conference in Toronto sponsored by the American Thoracic Society.

Asthma affects 22 million Americans, including 6 million children, according to the U.S. National Heart, Lung, and Blood Institute. The exact cause of the airway disease is not known, but doctors do know that there's an inherited tendency to develop asthma and allergies. They also suspect that early childhood exposure to certain respiratory infections and airborne irritants -- when the immune system is still developing -- plays a role in the development of asthma.

The Harvard study included 315 expectant mothers and their infants. All lived in an urban environment.

Mothers answered questions to assess their stress levels in different areas of their lives. Financial issues, home issues, community safety, relationship problems and medical issues were the most frequently reported negative events that the women experienced.

The researchers also measured dust mite exposure with samples obtained from the pregnant women's bedrooms. Samples of the cord blood were taken when the babies were born.

Because so many factors can affect the development of asthma and allergies, the researchers tried to adjust the data to account for maternal age, race, smoking, education, history of allergy and asthma, the child's gender and the season of birth. Even after controlling for these factors, however, they found that the number of stressors reported was linked to an increased risk of elevated IgE in the cord blood.

"A mom who had three or more negative events would have a 12 percent increased chance of having a baby with elevated cord blood IgE," Peters said.

Wright pointed out that elevated IgE is "suggestive" of an increased risk of developing asthma and allergy, but she noted that the association is not clear-cut.

Dr. Jennifer Appleyard, chief of allergy and immunology at St. John Hospital in Detroit , described the study as interesting but said that it had not demonstrated cause and effect. "Maybe what goes on before birth can have long-lasting effects," she said, but she added that she doesn't think this is something that most expectant mothers needed to be overly concerned about.

On the Web

Learn more about childhood asthma from the American Lung Association.

SOURCES: HealthDay News ; Junenette Peters, Sc.D., postdoctoral research fellow, Harvard Medical School, Boston; Rosalind Wright, M.D., assistant professor of medicine, Brigham and Women's Hospital and Harvard Medical School, Boston; Jennifer Appleyard, M.D., chief of allergy and immunology, St. John Hospital, Detroit; May 18, 2008, presentation, American Thoracic Society 2008 International Conference, Toronto
Author: Serena Gordon
Publication Date: May 31, 2009
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