Mother's prenatal stress predisposes their babies to asthma and allergy

ATS 2008, TORONTO—Women who are stressed during pregnancy may pass some of that frazzlement to their fetuses in the form of increased sensitivity to allergen exposure and possibly future asthma risk, according to researchers from Harvard Medical School who will present their findings at the American Thoracic Society’s 2008 International Conference in Toronto on Sunday, May 18.

“While predisposition to asthma may be, in part, set at birth, the factors that may determine this are not strictly genetic. Certain substances in the environment that cause allergies, such as dust mites, can increase a child’s chance of developing asthma and the effects may begin before birth,” said Rosalind J. Wright, M.D., M.P.H., assistant professor of medicine at Brigham & Women’s Hospital and Harvard Medical School.

Mother’s stress during pregnancy can also influence the babies developing immune system. While animal studies suggest that the combination of stress and allergen exposure during pregnancy may magnify the effects on the immune system, this is the first human study to examine this directly. The researchers analyzed levels of maternal stress and mother’s exposure to dust mite allergen in their homes while pregnant with respect to cord blood IgE expression—a marker of the child’s immune response at birth— in 387 infants enrolled in the Asthma Coalition on Community, Environment, and Social Stress (ACCESS) project in Boston.

They found increased levels of IgE expression in cord blood among infants whose mothers experienced higher level stress even when exposed to relatively low levels of dust mite during pregnancy. This indicates that mother’s stress during pregnancy magnified the effect of dust exposure on the child’s immune system such that the child’s immune response at birth may be altered even with lower levels of dust exposure in the home. The results held true regardless of the mother’s race, class, education or smoking history.