The effect of nitric oxide on uterine and umbilical artery flow velocity waveform in pre-eclampsia

Abstract

We compared the flow velocity waveforms of uterine and umbilical arteries in normotensive and pre-eclamptic patients at mid-gestation. In a randomised controlled trial we tested the effects of isosorbide dinitrate (ISDN, nitric oxide donor) patch therapy on the flow velocity waveform of pre-eclamptic patients at mid-gestation. The resistance indices (RI) of human uterine and umbilical arteries were higher in pre-eclamptic patients compared to the normotensive patients. ISDN patch therapy significantly reduced the increased RI values of the umbilical artery in pre-eclamptic patients without any change in systemic blood pressures, but the RI values of the uterine artery were not significantly attenuated. The change of the umbilical artery might be due to the improvement of end-diastolic flow velocity. These results suggest that the feto-placental circulation in pre-eclampsia, perhaps due to the disturbance of the endothelium-dependent vaso-relaxation system, and that ISDN therapy may improve the impaired endothelium dependent nitric oxide system.