Objective: To describe the characteristics of an obstetric population with influenza A/H1N1 (2009) infection, with a focus on the need for hospitalisation and complications.
Design: Cohort study.
Setting: Tertiary referral centre.
Population: Two hundred and eleven pregnant women with influenza A/H1N1 (2009) infection diagnosed by nasopharyngeal swab polymerase chain reaction (PCR).
Methods: Obstetric patients presenting to our centre were recruited and followed up. Data collected included demographic and clinical information.
Main outcome measures: H1N1 and pregnancy complications, and hospitalisation needs.
Results: The median age of the cohort was 29.0 years (range 16-42 years), the median gestation at referral was 23.0 weeks (range 4-38 weeks), the median time interval between illness onset and presentation was 2.0 days (range 1-7 days), and the median time interval between illness onset and commencement of oseltamivir was 2.0 days (range 1-11 days). Hospital admission was significantly associated with the presence of co-morbidity (OR 4.14, 95% CI 1.82-9.37, P = 0.0001), breathlessness (OR 5.2, 95% CI 2.19-12.41, P = 0.0003) and sore throat (OR 0.35, 95% CI 0.16-0.73, P = 0.005). There were two cases of pneumonia complicating H1N1 infection, but no mortality. Nine cases developed pregnancy complications. All women recovered.
Conclusions: The need for hospitalisation was significantly associated with breathlessness and co-morbidity. There was minimal morbidity and no mortality observed. We attribute this to early presentation, diagnosis and treatment.