Mothers know to try staying calm during pregnancy, as stress has been linked to behavioral and developmental problems for their babies. But now, a new study found that it also increases the risk for allergy-related asthma.
Stress hormones called glucocorticoids work to reduce inflammation; synthetic versions are used to treat allergic reactions. But when these same hormones are present in the body of a person who’s under chronic stress, they can trigger allergic responses instead of fighting them. Pregnant women have naturally higher levels of these hormones.
In the study, published in the American Journal of Physiology, doctors exposed groups of pregnant mice to either a single bout of stress, a synthetic hormone to mimic a stress response, or an inhibitor to block the release of stress hormones. The offspring of all the mice were exposed to allergens after birth.
“Only the offspring of stressed mothers demonstrated increased asthma susceptibility,” the researchers wrote, after just one stressful experience.