Pregnancy Enhances Ability to Fight Off Severe Flu, Study Shows

Pregnancy often feels like a balancing act for the immune system. While it’s true that expectant mothers face unique challenges—like increased vulnerability to certain infections or heightened concern over food recalls and illnesses—it turns out pregnancy isn’t all drawbacks. In fact, it can come with surprising immune system perks.

A new study from McGill University, published in Science, reveals an unexpected benefit: a natural defense mechanism in the nasal cavity that helps block severe flu infections during pregnancy. Researchers found that, in mice, pregnancy activates a specialized immune response that stops Influenza A virus from spreading to the lungs, where it can cause dangerous complications.

While an expectant mother’s immune system is compromised in some ways, this study suggests that pregnancy adaptations strengthen specific defenses to protect both mom and baby. “A mother needs to stay healthy to protect her developing baby, so the immune system adapts to provide stronger defenses,” explained Maziar Divangahi, PhD, co-lead author of the study in a press release. “This fascinating response in the nasal cavity is the body’s way of adding an extra layer of protection during pregnancy.”

By observing a unique type of immune cell in pregnant mice, researchers discovered that it produces a molecule that enhances the body’s antiviral response, particularly in the upper airways. This added defense could help prevent severe flu infections from taking hold, which is especially critical for pregnant individuals who face higher risks of flu complications like preterm birth.

Beyond a spot of good news, scientists are hopeful that these findings may lead to better ways of leveraging the body’s natural defenses against viruses. “Influenza A virus remains among the deadliest threats to humanity,” said first author Julia Chronopoulos. “This natural immunity in pregnancy could change the way we think about flu protection for expectant mothers.”

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