Pregnant women at increased mortality risk from swine flu
MedWire News: Mortality rates due to swine flu (influenza A H1N1) are significantly higher among pregnant women than the general population, US study results show.
"Changes in the immune, cardiac, and respiratory systems are likely reasons that pregnant women are at increased risk for severe illness with influenza," write the authors in the Journal of the American Medical Association.
Margaret Honein (Centers for Disease Control and Prevention [CDC], Atlanta, Georgia) and team studied data on all pregnant women with swine flu reported to the CDC between April and December 2009.
Specifically, the researchers assessed hospitalization, intensive care unit (ICU) admission, and mortality rates among pregnant women with swine flu, and investigated whether these rates were associated with the timing of antiviral treatment.
During the initial period of data collection (April–August), a total of 788 cases of swine flu among pregnant women were reported to the CDC. Of these women, 30 died.
Pregnant women represent around 1.0% of the US population, but they accounted for 5.0% of US deaths from swine flu during this period, the researchers note.
Among 509 women hospitalized with swine flu during this time, 115 (22.6%) were admitted to an ICU. Pregnant women who received antiviral treatment 4 or more days after symptom onset were six times more likely to be admitted to an ICU (56.9%) than those who were treated within 2 days after symptom onset (9.4%).
Further data collected up to the end of 2009 identified an additional 165 women with swine flu who were admitted to ICUs, of whom 56 died. Of these women, four (7.1%) died in the first, 15 (26.8%) in the second, and 36 (64.3%) in the third trimester of pregnancy.
Honein and team conclude: “Based on data from the first 4 months of the H1N1 pandemic and corroborated by data through December of 2009, pregnant women are disproportionately represented among deaths due to 2009 H1N1.”
They add: “Among pregnant women with 2009 influenza A (H1N1) influenza… early antiviral treatment appears to be associated with fewer admissions to an ICU and fewer deaths.”
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By Mark Cowen