Fig. 2.

Influenza A virus (IAV) infection of pregnant mice results in severe maternal disease and adverse pregnancy outcomes. A: nonpregnant (n = 10) and pregnant [embryonic day (E)10.5; n = 10–15] mice were infected with a sublethal dose of IAV or vehicle (mock) (n = 6–8/treatment) and monitored daily for changes in body mass. B: serum progesterone was quantified at 8 days postinoculation (dpi), corresponding to E18.5 in pregnant females. In the pregnant dams, spontaneous abortion was monitored over the course of infection (C), and litter size was quantified for each dam that carried her pregnancy to term (D). Bars represent means ± SE. Data were analyzed using repeated-measures ANOVA (A), two-way ANOVA (B), χ²-test (C), and Student’s t-test (D), where *P < 0.05.