Thromboxane synthetase inhibition produces maternal and fetal vasodilation during ovine pregnancy-induced hypertension: a Doppler flow velocimetric study.

ABSTRACT

Changes in maternal and fetal umbilical arterial vasoreactivity during ovine pregnancy-induced hypertension and following intravenous administration of CGS 12970 [3-methyl-2-(3-pyridyl)-1-indoleoctanoic acid] were assessed. Continuous wave Doppler flow velocimetry was used to assess vascular reactivity during normotensive baseline, during ovine pregnancy-induced hypertension triggered by a 72-hour fast, and following thromboxane synthetase inhibition with CGS 12970. Uterine and umbilical arterial systolic/diastolic flow ratios increased significantly with the onset of sustained hypertension. After thromboxane synthetase inhibition, uterine and umbilical artery systolic/diastolic flow ratios were not different from baseline, and maternal blood pressure had returned to baseline values. These data indicate that thromboxane produces maternal and fetal vasoconstriction during ovine pregnancy-induced hypertension. Furthermore, these data provide strong evidence that thromboxane synthetase inhibition allows vasodilation, resulting in improved maternal and fetal condition.