Perinatal and Maternal Outcomes in Critically ill Obstetrics Patients With Pandemic H1N1 Influenza A

Background: During the influenza pandemic of spring 2009, Manitoba had a disproportionate number of pregnant women who became critically ill. Information about these cases will be useful to help us understand the potential impact of future outbreaks and review critical illness in pregnancy. Methods: We describe the clinical details of six critically ill pregnant women with pandemic H1N1 2009 influenza virus admitted to two ICUs in Manitoba between March 1 and August 31, 2009. Results: Thirty adult pregnant women tested positive for pandemic H1N1 2009 virus in Manitoba. Six women were admitted to the ICU. The time from onset of symptoms to life-threatening deterioration was on average five days. Most patients presented with worsening fever and cough and had H1N1-positive contacts. Five of six patients (83%) were Aboriginal. Four of six cases occurred in the third trimester. These patients frequently required non-conventional ventilatory support such as high frequency ventilation or extracorporeal membrane oxygenation (ECMO). All patients received oseltamivir. Two patients died while in the ICU. Three of six patients had adverse perinatal outcomes, and there was one spontaneous abortion and one early preterm delivery. Conclusion: Pandemic H1N1 2009 influenza virus has the potential to cause severe illness in pregnant patients. Those patients requiring ICU admission for respiratory support have a high risk for poor fetal and neonatal outcome. The experience of this cohort underscores the appropriateness of public health measures directed at prevention and early treatment of H1N1 infection in pregnancy.