Prognosis of 2009 A(H1N1) influenza in hospitalized pregnant women in a context of early diagnosis and antiviral therapy.

Background: Initial reports suggested that novel A(H1N1) influenza virus (2009 A[H1N1]v) infection was significantly more severe in pregnant than in nonpregnant women. In Spain, antiviral therapy was recommended for pregnant women from the beginning of the 2009 pandemic. Methods: The prospective cohort study included consecutive pregnant and non-pregnant women of reproductive age with a proven diagnosis of 2009 A(H1N1)v admitted to any of the 13 participating Spanish hospitals between 12 June and 10 November 2009. Results: In total, 98 pregnant and 112 non-pregnant women with proven 2009 A(H1N1)v hospitalized during the study period were included. Influenza was more severe among non-pregnant patients than pregnant patients with respect to outcomes of both intensive care unit admission (18% versus 2%; P<0.001) and death (5 versus 0; P=0.06). Pregnant women had fewer associated comorbid conditions other than pregnancy (18% versus 44%; P<0.001); they were also admitted earlier than non-pregnant women (median days since onset of symptoms: 2 versus 3; P<0.001) and a higher percentage received early antiviral therapy (41% versus 28%; P=0.03). Neither a multivariate nor a matched cohort analysis found pregnancy to be associated with greater severity than that associated with hospitalized, seriously ill non-pregnant women. Conclusions: 2009 A(H1N1)v influenza was not associated with worse outcomes in hospitalized pregnant women compared with non-pregnant ones of reproductive age in a context of early diagnosis and antiviral therapy.