In the JournalsPerspective

Severe flu in pregnant women linked to adverse infant outcomes

Recent study findings published in Birth Defects Research demonstrate that infants born to mothers with severe influenza requiring ICU care were at risk of several adverse health outcomes, including prematurity.

Kim Newsome, MPH, from the CDC’s National Center on Birth Defects and Developmental Disabilities, and colleagues wrote that research conducted after the 2009 influenza A(H1N1) pandemic demonstrated that pregnant women who were infected had an increased risk for death or severe illness that required hospitalization or ICU care. However, few studies have assessed the outcomes of their children, they said.

The researchers analyzed data from 490 pregnant women infected with H1N1 between April and December 2009 in five states. Infants born to mothers who were infected during the 2009 influenza pandemic and required ICU care were more likely to be born younger than 37 weeks’ gestation (adjusted RR = 3.9; 95% CI, 2.7-5.6) and were more likely to have low birth weight (aRR = 4.6; 95% CI, 2.9-7.5) compared with infants born to 2,897 mothers without influenza. Infants whose mothers required ICU care were more likely to have Apgar scores of 6 or lower at 5 min. compared with infants born to uninfected mothers (aRR = 8.7; 95% CI, 3.6-21.2).

Newsome and colleagues did not observe a statistically significant risk for adverse infant outcomes for hospitalized pregnant women who did not require ICU care and pregnant women with influenza who did not require hospitalization.

“The message of this work is particularly timely in the midst of the current influenza season,” Sonja A. Rasmussen, MD, MS, professor in the Child Health Research Institute at the University of Florida, said in a press release. “Our study found that severely ill women with 2009 H1N1 influenza during pregnancy were more likely to have adverse birth outcomes, such as their baby being born preterm or of low birth weight. These findings support the importance of pregnant women receiving the influenza vaccine and of prompt treatment with antiviral medications for pregnant women.” – by Katherine Bortz

Disclosures: The authors report no relevant financial disclosures.

Recent study findings published in Birth Defects Research demonstrate that infants born to mothers with severe influenza requiring ICU care were at risk of several adverse health outcomes, including prematurity.

Kim Newsome, MPH, from the CDC’s National Center on Birth Defects and Developmental Disabilities, and colleagues wrote that research conducted after the 2009 influenza A(H1N1) pandemic demonstrated that pregnant women who were infected had an increased risk for death or severe illness that required hospitalization or ICU care. However, few studies have assessed the outcomes of their children, they said.

The researchers analyzed data from 490 pregnant women infected with H1N1 between April and December 2009 in five states. Infants born to mothers who were infected during the 2009 influenza pandemic and required ICU care were more likely to be born younger than 37 weeks’ gestation (adjusted RR = 3.9; 95% CI, 2.7-5.6) and were more likely to have low birth weight (aRR = 4.6; 95% CI, 2.9-7.5) compared with infants born to 2,897 mothers without influenza. Infants whose mothers required ICU care were more likely to have Apgar scores of 6 or lower at 5 min. compared with infants born to uninfected mothers (aRR = 8.7; 95% CI, 3.6-21.2).

Newsome and colleagues did not observe a statistically significant risk for adverse infant outcomes for hospitalized pregnant women who did not require ICU care and pregnant women with influenza who did not require hospitalization.

“The message of this work is particularly timely in the midst of the current influenza season,” Sonja A. Rasmussen, MD, MS, professor in the Child Health Research Institute at the University of Florida, said in a press release. “Our study found that severely ill women with 2009 H1N1 influenza during pregnancy were more likely to have adverse birth outcomes, such as their baby being born preterm or of low birth weight. These findings support the importance of pregnant women receiving the influenza vaccine and of prompt treatment with antiviral medications for pregnant women.” – by Katherine Bortz

Disclosures: The authors report no relevant financial disclosures.

    Perspective
    Pedro A. Piedra

    Pedro A. Piedra

    During pregnancy, women undergo a number of physiological changes to accommodate the developing fetus. The cardiovascular and respiratory changes are profound, with significant increases in cardiac output and oxygen demand. These compensatory changes that occur during pregnancy also place the pregnant woman and the fetus at increased risk from influenza-related pneumonia — an important cause of morbidity and mortality in pregnant women.

    The detrimental consequences of influenza virus infection to pregnant women are well known. However, less is known of its impact on their infants. The article by Newsome and colleagues on the outcomes of infants born to women with influenza A(H1N1)pdm09 highlight that severe influenza infection during pregnancy results in an increased risk for adverse outcomes to their infants such as prematurity, low birth weight, and low APGAR scores. It also reminds us of the importance of influenza vaccination during pregnancy and of early antiviral therapy.

    This winter season, the major circulating influenza virus is influenza A(H1N1)pdm09, and it is not too late to vaccinate against influenza virus infection.

    • Pedro A. Piedra, MD
    • Professor of virology, microbiology and pediatrics
      Baylor College of Medicine
      Infectious Diseases in Children Editorial Board member

    Disclosures: Piedra has served on scientific advisory boards for Sanofi-Pasteur, Astra-Zeneca and Genentech.