title: Pandemic 2009 influenza A(H1N1) virus illness among pregnant women in the United States.
abstract: BACKGROUND
  Early data on pandemic 2009 influenza A(H1N1) suggest pregnant women are at increased risk of hospitalization and death.
  
  
  OBJECTIVE
  To describe the severity of 2009 influenza A(H1N1) illness and the association with early antiviral treatment among pregnant women in the United States.
  
  
  METHODS
  Surveillance of 2009 influenza A(H1N1) in pregnant women reported to the Centers for Disease Control and Prevention (CDC) with symptom onset from April through December 2009.
  
  
  METHODS
  Severity of illness (hospitalizations, intensive care unit [ICU] admissions, and deaths) due to 2009 influenza A(H1N1) among pregnant women, stratified by timing of antiviral treatment and pregnancy trimester at symptom onset.
  
  
  RESULTS
  We received reports on 788 pregnant women in the United States with 2009 influenza A(H1N1) with symptom onset from April through August 2009. Among those, 30 died (5% of all reported 2009 influenza A[H1N1] influenza deaths in this period). Among 509 hospitalized women, 115 (22.6%) were admitted to an ICU. Pregnant women with treatment more than 4 days after symptom onset were more likely to be admitted to an ICU (56.9% vs 9.4%; relative risk [RR], 6.0; 95% confidence interval [CI], 3.5-10.6) than those treated within 2 days after symptom onset. Only 1 death occurred in a patient who received treatment within 2 days of symptom onset. Updating these data with the CDC's continued surveillance of ICU admissions and deaths among pregnant women with symptom onset through December 31, 2009, identified an additional 165 women for a total of 280 women who were admitted to ICUs, 56 of whom died. Among the deaths, 4 occurred in the first trimester (7.1%), 15 in the second (26.8%), and 36 in the third (64.3%);
  
  
  CONCLUSIONS
  Pregnant women had a disproportionately high risk of mortality due to 2009 influenza A(H1N1). Among pregnant women with 2009 influenza A(H1N1) influenza reported to the CDC, early antiviral treatment appeared to be associated with fewer admissions to an ICU and fewer deaths.
authors.affiliation: Epidemic Intelligence Service, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Siston
authors.forename: Sonja A
authors.initials: SA
authors.lastname: Rasmussen
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Honein
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Fry
authors.forename: Katherine
authors.initials: K
authors.lastname: Seib
authors.forename: William M
authors.initials: WM
authors.lastname: Callaghan
authors.forename: Janice
authors.initials: J
authors.lastname: Louie
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Doyle
authors.forename: Molly
authors.initials: M
authors.lastname: Crockett
authors.forename: Ruth
authors.initials: R
authors.lastname: Lynfield
authors.forename: Zack
authors.initials: Z
authors.lastname: Moore
authors.forename: Caleb
authors.initials: C
authors.lastname: Wiedeman
authors.forename: Madhu
authors.initials: M
authors.lastname: Anand
authors.forename: Laura
authors.initials: L
authors.lastname: Tabony
authors.forename: Carrie F
authors.initials: CF
authors.lastname: Nielsen
authors.forename: Kirsten
authors.initials: K
authors.lastname: Waller
authors.forename: Shannon
authors.initials: S
authors.lastname: Page
authors.forename: Jeannie M
authors.initials: JM
authors.lastname: Thompson
authors.forename: Catherine
authors.initials: C
authors.lastname: Avery
authors.forename: Chasisity Brown
authors.initials: CB
authors.lastname: Springs
authors.forename: Timothy
authors.initials: T
authors.lastname: Jones
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Williams
authors.forename: Kim
authors.initials: K
authors.lastname: Newsome
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Jamieson
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D004196:Disease Outbreaks; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000188:drug therapy / Q000401:mortality*; D007362:Intensive Care Units; D010343:Patient Admission / Q000706:statistics & numerical data; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy / Q000401:mortality*; D011264:Pregnancy Trimesters; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000998:Antiviral Agents
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