2009 pandemic influenza A (H1N1) in pregnancy: a systematic review of the literature

Am J Obstet Gynecol. 2011 Jul;205(1):10-8. doi: 10.1016/j.ajog.2010.12.033. Epub 2011 Feb 23.


To summarize the literature regarding 2009 H1N1 influenza A during pregnancy, we conducted a systematic literature review using a PubMed search and other strategies. Studies were included if they reported 2009 H1N1 influenza in pregnant women as original data. In all, 2153 abstracts were reviewed, and a total of 120 studies were included. Data were extracted regarding number of cases, additional risk factors for influenza-associated complications, treatment, and maternal and pregnancy outcomes. Authors were contacted to determine the extent of overlap when it was suspected. Pregnancy was associated with increased risk of hospital and intensive care unit admission and of death. Pregnant women who received delayed treatment with neuraminidase inhibitors or who had additional risk factors were more likely to develop severe disease. Preterm and emergency cesarean deliveries were frequently reported. These results reinforce the importance of early identification and treatment of suspected influenza in this high-risk population.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Antiviral Agents / therapeutic use
  • Cesarean Section / statistics & numerical data
  • Female
  • Hospitalization / statistics & numerical data
  • Humans
  • Infant, Newborn
  • Influenza A Virus, H1N1 Subtype / drug effects
  • Influenza A Virus, H1N1 Subtype / isolation & purification*
  • Influenza, Human / complications
  • Influenza, Human / drug therapy
  • Influenza, Human / epidemiology*
  • Influenza, Human / virology
  • Intensive Care Units / statistics & numerical data
  • Neuraminidase / antagonists & inhibitors
  • Pandemics / statistics & numerical data*
  • Pregnancy
  • Pregnancy Complications, Infectious* / drug therapy
  • Pregnancy Complications, Infectious* / epidemiology
  • Pregnancy Complications, Infectious* / virology
  • Pregnancy Outcome
  • Risk Factors
  • Severity of Illness Index


  • Antiviral Agents
  • Neuraminidase