Although vaccination induces an inflammatory response during pregnancy, the magnitude and the duration of response is much lower and shorter, respectively, for influenza vaccination than viral infection.27 Like infection, influenza vaccination during pregnancy has been reported to induce a transient increase in the
levels of a number of proinflammatory
cytokines, including interleukin 6, tumor necrosis factor α, and C - reactive protein.27 - 30 Studies on mice found an association between high interleukin - 6
levels during pregnancy and
abnormal behavior and brain structure.19 However, in epidemiological studies, associations between maternal
cytokine levels and ASD have been mixed.