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Presentation of influenza a in pregnancy during the 2003-2004 influenza season

      Objective

      Pregnant women with influenza have been reported to have excess morbidity and mortality. We describe the clinical course of influenza in pregnant women followed at our institution during the 2003-2004 influenza season.

      Study design

      Prospective evaluation of all pregnant women diagnosed with influenza A between November 1, 2003 and February 29, 2004. Pregnant women presenting with a flu-like illness were evaluated using a rapid diagnostic test and/or culture. Patients were admitted in accordance with protocols prospectively developed. Amantadine or rimantadine was prescribed for women with a laboratory-confirmed diagnosis.

      Results

      Influenza A was confirmed in 102 patients. All viral isolates obtained were of the H3N2 strain. Mean gestational age at diagnosis was 26.0 ± 9.4 weeks, with 48% of cases occurring in the first or second trimester. Cough was the most commonly reported symptom (89%), followed by myalgia (53%), rhinorrhea (50%), and nausea/vomiting (36%). Forty-five percent of patients reported contact with a person who had influenza-like symptoms. Mean maximum heart rate was 122 ± 20 bpm. Eleven percent of patients had a maximum heart rate >140 bpm. Mean temperature recorded was 38.1 ± 3.0 C. Complications of influenza A included pneumonia (12%), meningitis (1%), and myocarditis (1%). One patient required intubation. There were no deaths. Thirteen percent of patients received the flu vaccine prior to developing symptoms; however only 3 of those women were vaccinated >2 weeks prior to the onset of symptoms. To date, 57 women have delivered with no neonatal complications attributable to influenza. There were no complications of treatment with amantadine or rimantadine.

      Conclusion

      Influenza A in pregnancy is characterized by cough, myalgia, rhinorrhea, and nausea/vomiting. Profound tachycardia disproportionate to maternal fever uniquely affected the majority of women in our cohort. Pneumonia complicated 1 in 8 cases; however, the anticipated excess maternal morbidities and mortality did not occur.