The results showed that the levels of serum SIRT1 in patients with severe preeclampsia decreased, compared with the mild group (p < 0.0001) (Figure 1A); the peak-to-trough ratio of blood flow velocity, pulsatility index and resistance index were all increased in patients with severe preeclampsia, compared with the mild group (p < 0.001; p < 0.0001) (Figure 1B-D). Here, SIRT1 is linked to preeclampsia.