Reduced contractile effect of endothelin-1 and noradrenalin in human umbilical artery from pregnancies with abnormal umbilical artery flow velocity waveforms.

This study on the human umbilical artery was undertaken in order to elucidate possible correlations between changes in response to vasoactive substances in vitro and abnormal umbilical artery flow velocity waveforms in vivo associated with preeclampsia and intrauterine growth retardation. The vascular reactivity to endothelin-1, noradrenalin, serotonin, the thromboxane A2 analogue U46619, substance P and prostacyclin was determined in umbilical artery segments from 13 normal pregnancies and 29 pregnancies complicated with preeclampsia and/or intrauterine growth retardation with normal or abnormal umbilical flow velocity waveforms. The contractile effect in vitro of endothelin-1 and noradrenalin was reduced in segments from pregnancies complicated by abnormal umbilical flow velocity waveforms in vivo. No differences were detected in the contractile effect of serotonin and U46619, or in the relaxatory effect of substance P and prostacyclin. In conclusion, endothelin-1- and noradrenalin-related mechanisms could be involved in the abnormal umbilical flow velocity waveforms associated with preeclampsia and intrauterine growth retardation.