Severe Flu Increases Risks for Pregnant Women and Their Babies

A new study shows pregnant women who are hospitalized in the intensive care unit (ICU) with influenza (flu) are four times more likely to deliver babies prematurely and four-and-a-half times more likely to have a baby of low birth weight. In the study, researchers compared 490 pregnant women with the flu, 64 of whom were so ill they were admitted to a hospital ICU, and 1,451 who did not have the flu. They found babies of the most seriously ill women were eight times more likely to have low Apgar scores, a measure of a baby’s color, heart rate, reflexes, muscle tone and breathing in the minutes after birth. According to Sonja Rasmussen, MD, of the University of Florida College of Medicine, it’s not clear what affected these newborns, but it’s suspected that “when moms are in the ICU, they often need help breathing, they need a ventilator to breathe for them, and it may be that there is some period of time [when] they aren’t breathing well enough to get adequate oxygen to the baby.” In addition, she says it’s possible nutrition plays a role. “When you’re having trouble breathing, you have trouble eating, and it may be that Mom wasn’t getting good nutrition during her time in the ICU,” Dr. Rasmussen explains. In pregnant women with the flu who were able to stay home (and even those admitted to the hospital but not admitted to the ICU), there was no significant increase in risk for adverse health outcomes for their babies.

Dr. Rasmussen says the findings underscore the importance of pregnant women receiving the influenza vaccine and getting prompt treatment with antiviral medications. Prior to the 2009 pandemic, only approximately 20 percent to 30 percent of pregnant women got the flu vaccine. After that, doctors and health professionals strongly urged vaccination, and the rate increased to approximately 50 percent.