Depressed pregnant women tend to have stronger response to flu infection

October 29, 2009 by Shawn Douglas
Filed under: News, Pregnancy

Depressed pregnant women could be at a higher level of risk when receiving flu vaccinations says a recent study out of Ohio State University.

Typically, a flu vaccination promotes an inflammatory response by the immune system. This response is normal and is how the vaccine actually helps; it gears the immune system up to successfully repel the full infection if it should occur. The reaction the body has to the vaccine should be weak and brief.

However, Ohio State researchers have found that the reaction to the flu vaccine in depressed pregnant women was vigorous and prolonged. This led researchers to believe that the immune systems of pregnant women suffering from depression weren’t functioning as expected, suggesting that receiving the flu vaccine is a favorable course of action for such women.

“Inflammatory responses to vaccination do no harm, are mild, and typically go away within a few days,” explained Lisa Christian, assistant professor of psychiatry at Ohio State University and lead author of the study.

“But an extended inflammatory response to vaccination, such as the one seen in women with the most depressive symptoms, isn’t expected, and it serves as a way to estimate how somebody might respond to an actual infection or illness.”

Plenty of research exists showing how certain functions of a typical pregnant woman’s immune system can be temporarily diminished to protect the developing fetus from inflammation in the mother’s body caused by other illnesses. However, little research has been conducted on the links between pregnant women and things like depression and stress.

During the study, 22 pregnant women were assessed for depressive symptoms, blood samples were taken, and the seasonal flu vaccine was given. Follow-up blood draws were taken about a week later to analyze the levels of MIF, an inflammation-promoting protein that suppresses many of the substances in the blood that routinely fight against inflammation. Researchers found that the women assessed to have the most traits of depression had twice the levels of the MIF protein than women assessed to have few symptoms of depression.

“In the context of an actual illness, the response would be expected to be much more robust and more extended,” said Christian. “And then we might have concerns about whether women who show an exaggerated inflammatory response would be more susceptible to complications.”

The team recognized that more studies need to be conducted across larger sample sizes, and the team hopes to eventually follow the women through pregnancy to find links between psychological factors and birth outcomes.

The research is set to appear in the journal Brain, Behavior, and Immunity later next month.