Representative FACS dot plots of pro-inflammatory cytokines (IFN-γ, IL-21, TNF-α, and IL-2) and anti-inflammatory cytokines (IL-4 and IL-10) produced by CD8+ T cells are shown in Fig. 5A. When comparing the pro-inflammatory and anti-inflammatory cytokine secretion from CD8+ T cells in the AF mothers with that of the NAF mothers before, during, and after AVT, we found that the amount of IFN-γ-secreting CD8+ T cells in AF mothers was significantly higher than that of NAF mothers at 26–28 weeks of gestation and at 6–8 weeks postpartum (p = 0.046, p = 0.035). Here, IL21 is linked to atrial fibrillation.