Vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) cause vasodilation. We examined the vasomotor response of isolated placental vessels to VEGF and PlGF in normal (group I) and intrauterine growth retardation (IUGR)-complicated pregnancy (group II). Rings of vessels were prepared in vitro and mounted on the vessel myograph plunged in tissue bath. The magnitude of dilation to increased doses of VEGF and PlGF has been studied. VEGF is a more potent vasodilator than PlGF. Both, VEGF- and PlGF-induced vasorelaxation was diminished in the IUGR (group II) nearly by half, compared to control (group I). Relative placental nitric oxide deficiency, or decreased sensitivity to VEGF and PlGF may contribute to the development of high impedance fetoplacental circulation.