Umbilical and uterine Doppler velocimetry and prostaglandin levels in preeclampsia

Eleven preterm patients with severe preeclampsia underwent Doppler velocimetry prior to cesarean section. Maternal venous blood and umbilical arterial and venous samples were collected for prostacyclin and thromboxane determination by radioimmunoassay. Umbilical artery pulsatility index correlated positively with umbilical artery thromboxane B₂ levels (r = 0.76; P < 0.05) and maternal thromboxane levels (r = 0.78; P < 0.05). We conclude that the vasoactive action of thromboxane A₂ may alter placental resistance.