NO plays an important role in mediating NP vasodilation, while defective endothelial NO synthesis and bioavailability has been associated with preeclampsia.28,29 This is the first study to reveal ex vivo–derived STBMV and STBEX isolated from placental perfused lobes to have less eNOS activity in preeclampsia in comparison to controls. Here, NOS3 is linked to preeclampsia.