For elective cesarean sections, the irisin levels in cord serum for normal pregnancies (97.1 ± 15.7 ng/mL) and with mild preeclampsia (97.3 ± 1 6.6 ng/mL) were significantly lower than for the cohort of mild preeclampsia for vaginal delivery (120.9 ± 14.81 ng/mL), and additionally, the irisin level in cord serum correlated with the birth weight of newborns [134] (Table 3). Here, FNDC5 is linked to preeclampsia.