FOXO1 and preeclampsia: While the pathophysiology of early-onset preeclampsia is inappropriate placental formation and development, the possible cause of late-onset preeclampsia may be premature placental aging; therefore, regardless of gestational week, FoxO1 and SIRT 2 levels may be decreased more in the late-onset group compared to both the early-onset preeclampsia group and the healthy group.