Figure 4From: Return of pandemic H1N1 influenza virus The percentage of positive cases for pregnant women. The percentages (out of the 21–40 age group) of pregnant women hospitalized due to influenza-like syndrome and infected with the pandemic 2009 influenza virus from 2009-today (2013). Three periods of infection are presented (x axis). *P < 0 · 05 using the chi-square test.Back to article page