Plasma endothelin-1 and mean arterial pressure in the prediction of pre-eclampsia

To determine whether increased first trimester plasma endothelin-1 and/or increased midtrimester mean arterial blood pressure detected in pregnant women who are free of symptoms can predict the subsequent development of pre-eclampsia.

Eighty pregnant women were successfully followed from 10 weeks gestation until delivery. Pre-eclampsia and eclampsia developed in 29 and 2 women, respectively, whereas 49 women remained normotensive. Plasma endothelin-1 was determined in the first trimester (10-12 weeks gestation) by a competitive radioimmunoassay.

First trimester plasma endothelin-1 levels in pregnant women who subsequently developed mild, severe pre-eclampsia and eclampsia were significantly higher than those of pregnant women who remained normotensive. The release of endothelin-1 increases with the severity of the disease, age, body mass index and mean arterial blood pressure. The predictive values of plasma endothelin-1 for pre-eclampsia were: sensitivity 96.8%, specificity 51%, positive predictive value 55.5% and negative predictive value 91%, whereas those of MAP were 48.4, 45, 35.7 and 58%, respectively.

Determination of first trimester plasma endothelin level may be a valuable marker to identify 55.5% of individuals at high risk of developing pre-eclampsia, if combined with midtrimester MAP, the positive predictive value increases to 68.2%.