Epidemiology and Clinical Outcomes of Hospitalizations for Acute Respiratory or Febrile Illness and Laboratory-Confirmed Influenza Among Pregnant Women During Six Influenza Seasons, 2010-2016

J Infect Dis. 2020 Apr 27;221(10):1703-1712. doi: 10.1093/infdis/jiz670.


Background: Pregnant women are at increased risk of seasonal influenza hospitalizations, but data about the epidemiology of severe influenza among pregnant women remain largely limited to pandemics.

Methods: To describe the epidemiology of hospitalizations for acute respiratory infection or febrile illness (ARFI) and influenza-associated ARFI among pregnant women, administrative and electronic health record data were analyzed from retrospective cohorts of pregnant women hospitalized with ARFI who had testing for influenza viruses by reverse-transcription polymerase chain reaction (RT-PCR) in Australia, Canada, Israel, and the United States during 2010-2016.

Results: Of 18 048 ARFI-coded hospitalizations, 1064 (6%) included RT-PCR testing for influenza viruses, 614 (58%) of which were influenza positive. Of 614 influenza-positive ARFI hospitalizations, 35% were in women with low socioeconomic status, 20% with underlying conditions, and 67% in their third trimesters. The median length of influenza-positive hospitalizations was 2 days (interquartile range, 1-4), 18% (95% confidence interval [CI], 15%-21%) resulted in delivery, 10% (95% CI, 8%-12%) included a pneumonia diagnosis, 5% (95% CI, 3%-6%) required intensive care, 2% (95% CI, 1%-3%) included a sepsis diagnosis, and <1% (95% CI, 0%-1%) resulted in respiratory failure.

Conclusions: Our findings characterize seasonal influenza hospitalizations among pregnant women and can inform assessments of the public health and economic impact of seasonal influenza on pregnant women.

Keywords: hospitalization; influenza; pregnant.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Cohort Studies
  • Female
  • Fever / therapy*
  • Global Health
  • Hospitalization*
  • Humans
  • Influenza, Human / epidemiology
  • Influenza, Human / therapy*
  • Middle Aged
  • Pregnancy
  • Respiratory Tract Diseases / epidemiology
  • Respiratory Tract Diseases / therapy*
  • Retrospective Studies
  • Seasons
  • Time Factors
  • Young Adult